Part 2%3A Lake and Watershed Management Plan, Carlinville, Macoupin County, Illinois

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Part 2
Lake and Watershed Management Plan
Carlinville, Macoupin County, Illinois
INTRODUCTION
Pursuant to the information collected and the conclusions derived from the
Diagnostic Study (Part 1) of this Report, a Lake and Watershed Management Plan (Part
2) was developed by investigating potential alternatives for restoring the water quality
and enhancing the recreational and aesthetic qualities of Lake Carlinville and its
watershed. This plan should facilitate future implementation of recommendations and
serve as a vehicle for additional funding through the Nonpoint Source Pollution Control
Program or Illinois Clean Lakes Program. The U.S. EPA funded 56 percent of Part 2
under a Section 319 Grant, with the remaining 44 percent funding contributed by the
City of Carlinville. While the U.S. EPA provided funding, the Illinois EPA was
responsible for grant administration and program management. HDR | Cochran &
Wilken, Inc. (HDR | CWI) completed the Feasibility Study, with assistance from the City
of Carlinville, the Macoupin County Soil and Water Conservation District, United States
Department of Agriculture - Natural Resources Conservation Service, Illinois
Department of Natural Resources, and the Illinois EPA.
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A. IDENTIFICATION OF WATER QUALITY AND USE IMPAIRMENT PROBLEMS
Current and historical data discussed in the Diagnostic Section (Part 1) served as
the basis for the following discussions, which summarize the impairments for Lake
Carlinville and its watershed.
1. Soil Erosion and Excess Nutrient Loading
Excessive erosion significantly contributes to sediment and nutrient loadings
entering Lake Carlinville. The prevailing land use types (agriculture and forest) and
practices dictate much of the soil erosion and nutrient transport processes within the
Lake Carlinville watershed. Of the nearly two-thirds of the watershed in agricultural
production, soybeans and small grains tend to be the only crops that are tilled
conservatively (Limno-Tech, 2005 and USDA-NRCS personal communication, 2006).
Forested regions of the watershed are sources of soil erosion and nutrient transport as
well. For the nearly one-fourth of the watershed that is forested, many gullies and
ravines are present. Ephemeral and gully erosion sediment delivery rates range from
75 to 90%. Streambank and lake shoreline erosion have high sediment and nutrient
delivery rates within the Lake Carlinville watershed, as nearly all of the eroded soils are
deposited within the receiving waters (i.e., Honey Creek and Lake Carlinville). The
primary sources of soil erosion within the watershed are sheet and rill erosion (mostly
from agricultural or crop land) and the sediment and nutrient delivery from ephemeral
gully erosion and combined gully, streambank, and shoreline erosion. Ephemeral gully
and gully erosion tend to occur along the transition area between fields and forests and
within the forested areas of the watershed.
Another source of erosion in the watershed is erosion along Honey Creek, the
major tributary to Lake Carlinville. Streambank erosion along Honey Creek and
subsequent sediment delivery to Lake Carlinville has been documented (USDA-NRCS,
1996 and 2003), although no measured streambank erosion data has been gathered for
Honey Creek (Ford personal communication, 2006). Before initiating specific
streambank stabilization projects, Honey Creek must be evaluated to determine the
various levels of streambank erosion and to prioritize problem areas by the severity of
erosion.
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Similar to streambank erosion, shoreline erosion along Lake Carlinville is another
source of sediment and nutrient transfer to the lake. Lake shoreline erosion can be
caused by the following activities or actions: wind and wave action, pedestrian and
livestock traffic, water level fluctuations caused by either drought or periodic lake level
draw downs, and a lack of near-shore vegetation. Shoreline erosion impairs lake usage
and access by increasing lake turbidity, decreasing lake storage capacity, and
damaging valuable lakeshore property. The loss of shoreline soils may also jeopardize
the stability of infrastructure, such as bridges, roads, and docks. The 2006 shoreline
erosion survey determined that approximately 5,703 meters (18,709 ft.) had
experienced some degree of erosion, which varied from slight to severe.
The horizontal length of each eroded zone was estimated and a vertical
measurement was applied to the following criteria: a bank height of 1.0 to 3.0 ft. was
classified as slight, greater than 3.0 ft. and less than 8.0 ft. was classified as moderate,
and greater than 8 ft. was classified as severe. Approximately 341 meters (1,118 ft.) of
shoreline was found to have severe erosion, 1,293 meters (4,243 ft.) exhibited
moderate erosion, and 4,068 meters (13,348 ft.) of shoreline was found to have slight
erosion. According to the 2006 shoreline erosion survey, approximately 54.4% of the
10.5 km (6.52 miles) shoreline was unprotected and has been negatively impacted by
erosion. The typical form of erosion observed at these locations was an exposed and
undercut bank that, throughout time, will gradually allow the upper reaches of the
shoreline slope to collapse. Photographs illustrating shoreline erosion at Lake
Carlinville are shown in Appendix D.
2. Excessive Lake Sedimentation
An estimated 1,425,009 cubic yards of sediment have been deposited throughout
the lake between 1939 and 2006. This volume of accumulated sediment represents an
approximate 37.6 percent water storage capacity loss for the entire lake over its 67-year
history. Most of the accumulated sediment is located throughout the upper end of the
lake, where Honey Creek enters the lake.
Accumulated sediments are generated from erosion within the watershed, as well
as from the decomposition of dead and decaying plant (i.e., algae, macrophytes, and
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trees) and animal matter (i.e., fish) within the lake. By their origin, these sediments are
high in organic content and are nutrient rich, which create a loosely compacted
substrate over the bottom of the lake. This loose, low density bottom sediment can be
resuspended by bottom feeding fish, high wind conditions, boat turbulence, and storm
inflows. As a result, the water quality in Lake Carlinville has been impacted by elevated
suspended solids levels and decreased water transparencies.
Excessive sedimentation can negatively impact any lake that serves as a public
water supply or that is used for recreational purposes, as there is the possibility of
burying intake structures, reducing the lake’s original water storage capacity,
contributing to shallow water depths, and impacting aquatic habitat. Reservoir
sedimentation is a natural process that can be accelerated or slowed by human
activities in the watershed. In most cases, agricultural and developmental activities in
the watershed increase sediment delivery to the lake due to increased exposure of the
soil material to erosive forces.
3. Degraded Water Quality
Soil erosion and nutrient transport from the watershed have degraded Lake
Carlinville water quality. Excessive sediment and nutrients in the lake have also been
connected to various lake water quality issues. Water quality concerns include
chemical and physical conditions such as excessive solids (discussed previously),
phosphorus, manganese, and high turbidity.
As mentioned in the Diagnostic Section, Lake Carlinville was placed on the
303(d) list of impaired waters for phosphorus and manganese in 2006. Other
impairments identified were total suspended solids and algae, although there are no
standards for these parameters. In 2006, a TMDL study was initiated for the Macoupin
Creek Watershed, which includes the Lake Carlinville watershed. Illinois EPA (2006)
determined that the potential sources contributing to Lake Carlinville’s impairments are:
natural background and seasonal hypolimnetic anoxia for manganese; and agricultural
runoff and seasonal hypolimnetic anoxia for total phosphorus. Lake Carlinville’s status
on the 303(d) list is a result of available data indicating that at least one designated use
is not being supported or is threatened (Illinois EPA, 2006).
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The sources of Lake Carlinville’s high in-lake nutrient concentrations include
inflows from the agricultural watershed runoff, resuspension of sediment, seasonal
internal regeneration from anoxic lake bottom sediments, both living and dead
plant/animal matter within the lake, stream bank and shoreline erosion, and atmospheric
deposition. The phosphorus and nitrogen nutrient budgets representing the 2006-07
monitoring year indicate that watershed runoff provided the majority of the phosphorus
and nitrogen influx to the lake. Internal regeneration was estimated to a minor
contribution to the total phosphorus and nitrogen influxes.
In addition to water quality impairments identified by the 303(d) list, turbidity or
murkiness is another water quality issue that affects Lake Carlinville. During the lake’s
primary recreational use period from April through September, water clarity averaged
19.6-inches at Site 1, 16.6-inches at Site 2, and 11.5-inches at Site 3 in 2006. As a
reference, the Illinois EPA swimming guidelines suggest that a Secchi depth of 24
inches fully supports recreational swimming. Turbidity can be affected by the presence
of suspended solids such as soil particles, resuspended bottom sediments, and both
living and dead plant/animal matter. The aesthetics of the lake are reduced by the
brown, green and/or murky water appearance. Increased turbidity can also inhibit the
growth of aquatic vegetation by limiting light penetration into the water column. It is
likely that turbidity is the main reason the 2006 aquatic macrophyte survey for Lake
Carlinville showed a very sparse aquatic macrophyte population.
The factors that have contributed to Lake Carlinville’s poor water quality include
runoff from a primarily agricultural watershed, large quantities of accumulated lake
sediment and nutrients, excessive phytoplankton growth (particularly blue-green algae),
and streambank and lake shoreline erosion. The Lake Carlinville watershed is highly
agricultural, which often reflects higher soil gross erosion rates and higher sediment and
nutrient delivery ratios. Compared to other land use types, agricultural fields tend to
erode more easily due to their increased exposure to wind and precipitation.
Streambank and shoreline erosion add to the amount of sediment and nutrients being
transferred to the lake. Fine-grained particles (i.e., silt and clay) from erosion can
remain suspended in the water column for extended periods of time. Resuspended
sediments may also release nutrients into the water column, thereby contributing to
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increased turbidity and algal growth. Sediment resuspension and turbidity resulting
from wind and wave action in shallow, near-shore areas was evident and has reduced
the aesthetic quality of Lake Carlinville.
Historical and Phase 1 phytoplankton data indicate high counts of algae in Lake
Carlinville, which increases overall lake turbidity. During the summer months, blue-green
algae (Cyanophyta) tends to be the dominant algal taxa within Lake Carlinville.
The blue-greens are considered especially undesirable for aesthetics because of their
tendency to form scum and mats, and are not a desirable food source for most aquatic
organisms (i.e., zooplankton and small fish). In addition, blue-greens can become toxic
and can cause taste and odor problems, which can complicate water treatment and
impact the public water supply.
4. Unbalanced Aquatic Vegetative Community
The aquatic plant community within Lake Carlinville includes aquatic
macrophytes (i.e., plants visible and identifiable to the naked eye) and phytoplankton
(i.e., algae). Both are an extremely important component of a balanced lake
ecosystem. Algae can provide food for aquatic insects, zooplankton and fish, and
oxygen, which is beneficial to all organisms. However, an overabundance of
phytoplankton (algae) can result in adverse effects such as: increasing overall lake
turbidity; shading out and limiting the growth of macrophytes; algal blooms and surface
scums that detract from lake aesthetics; night time algal respiration and/or rapid algal
die-offs that can deplete dissolved oxygen levels and severely stress the fish
population.
Algal growth is stimulated by high concentrations of nutrients in the water
column. Measurements of inorganic phosphorus and inorganic nitrogen obtained during
the Phase 1 monitoring period were generally above the levels known to contribute to
nuisance algal growth, (0.01 mg/l for inorganic phosphorus and 0.30 mg/l for inorganic
nitrogen (Sawyer, 1952)). The Phase 1 data shows that the algal population was
excessive during the 2006-07 monitoring year, reaching bloom conditions throughout
most of the summer. When bloom conditions occur, the algal induced turbidity reduces
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light penetration throughout the water column and adversely impacts macrophyte
growth.
Within Lake Carlinville, phytoplankton or blue-green algae populations dominate
over aquatic macrophytes, as well as beneficial algal populations. The over abundance
of these nuisance microscopic plants has been linked to several documented cases of
taste and odor problems in the public water supply. Excessive lake turbidity and
phytoplankton dominance have also stunted the lake’s aquatic macrophyte population,
as only two species were observed within the lake. The 2006-aquatic plant survey for
Lake Carlinville identified water willow (Decodon verticillatus) and creeping water
primrose (Jussiaea repens var. glabrescens) as the only macrophyte species
encountered in the lake. These emergent species were generally found to inhabit
shallow waters less than 2 feet deep. No submerged (underwater) species were
encountered during the aquatic plant survey. Turbidity along the littoral zones is the
primary reason for the sparse and limited aquatic macrophyte population densities
within Lake Carlinville. Sporadic aquatic plant populations could secondarily be
attributed to high nutrient levels that contribute to phytoplankton dominance.
5. Unbalanced Fishery
Excessive sedimentation and lack of suitable habitat and spawning areas are the
main contributors to the fair to poor fishery at Lake Carlinville (Pontnack personal
communication, 2006). Excessive nutrient levels and the sparse aquatic macrophyte
population have also contributed to a diminished sport fish population. The District 14
IL DNR fisheries biologist has reported that no fish have been stocked within Lake
Carlinville since 1994 due to the existing lake conditions. Population and creel census
surveys completed every three years by IL DNR fisheries biologists indicate that the
largemouth bass, bluegill, and white crappie populations within the lake have been
variable and that undesirable fish species such as black bullhead catfish, warmouth,
yellow bullhead catfish, common carp, yellow bass, and green sunfish have become
well established (Pontnack personal communication, 2006).
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B. OBJECTIVES OF THE LAKE CARLINVILLE WATERSHED PLAN
Like most lakes and reservoirs, Lake Carlinville reflects its watershed. Thus,
many of the identified lake and watershed impairment issues are often interrelated. The
goal of the Lake Carlinville Watershed Plan is to address the problems identified in the
previous section, to protect and enhance existing lake and watershed uses, to increase
recreational access and opportunities, and to improve the overall water quality of the
lake. The watershed plan objectives listed below have been determined based on the
impairments discussed previously.
1. Improve Water Quality
2. Enhance Lake Aesthetics and Recreational Opportunities
3. Promote Lake and Watershed Restoration
The following recreational use improvements will be achieved by addressing the
objectives listed above.
1. Preserve and enhance existing lake uses: public water supply, fishing, boating,
and aesthetics.
2. Increase local interest by increasing water clarity and improving water quality.
3. Increase areas available for recreational uses by maintaining and/or increasing
the depth in the upper reaches of the lake.
4. Increase the sport fish populations in the lake by improving habitat, combined
with stocking and continued fisheries management.
C. ALTERNATIVES FOR ACHIEVING THE WATERSHED PLAN OBJECTIVES
Each of the objectives listed in Section B has several alternative approaches or
solutions that have been evaluated and considered. These restoration and
management alternatives are described within Section C. Recommended actions for
the Lake Carlinville Watershed Plan are summarized in Table 28 (page 113), which also
includes ranges of unit costs, proposed units, ranges of estimated costs, estimated load
reductions, and financial and technical assistance. For most of the objectives, there are
one or more alternatives that clearly stand out relative to cost, benefits, and feasibility.
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Although taking no action whatsoever is also an alternative, the long-term cost of no
action is often too high. Delaying any necessary actions could lead to more expensive
projects at a later date as a result of continued lake degradation (eutrophication) and
inflation of project costs.
Objective #1: Improve Water Quality
The sediment and nutrients entering the lake and the accumulated sediment at
the bottom of the lake both contribute to poor water quality and should be addressed
before other alternatives are considered. In order to improve water quality in Lake
Carlinville and the surrounding watershed, a combination of proactive and retroactive
approaches will be necessary. The sources of accumulated sediment in the lake
include runoff from the watershed, eroded stream banks in the watershed, and eroded
lake shoreline. The best way to manage the accumulation of sediment is to implement
measures in the watershed that will reduce the amount of sediment entering the lake.
This includes implementing best management practices (BMPs) throughout the
watershed and stabilizing the lake shoreline to prevent erosion. In addition to
preventing sediment from entering the lake, removal of accumulated sediment will be
necessary. To this end, the following actions items have been identified to improve
water quality throughout the Lake Carlinville watershed.
A. Reduce the Amount of Sediment and Nutrients Entering the Lake;
B. Remove Accumulated Sediment from the Lake; and
C. Stabilize and Protect Eroded Lake Shoreline Areas.
Action Item A. Reduce the Amount of Sediment and Nutrients Entering the Lake
Alternative Actions
Reducing nonpoint source pollution from the watershed is perhaps the most
important action item because it is a measure that will protect the lake for many
generations. Alternatives listed for Action Item A protect the lake by managing sources
of nonpoint pollution (e.g., unprotected soil in agricultural fields, eroding land, and
excess fertilizer application). Due to the wide variety of watershed management
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alternatives and BMPs, Action Item A was subdivided into two groups: non-structural
and structural alternatives.
The US EPA’s Handbook for Developing a Watershed Plan to Restore and
Protect Our Water (2005) defines non-structural practices as “any practice that
prevents or reduces runoff problems in receiving waters by reducing the generation of
pollutants and managing runoff at the source. This type of practice may be included in
a regulation or may involve voluntary pollution prevent devices.” For this study, the
following non-structural alternatives and BMPs were considered:
· Nutrient Management Plans
· Crop Rotations
· Conservation Tillage Practices
· Conservation Buffers
· Inspect and Upgrade Septic Systems
· Changing Landscaping Practices
· Livestock Exclusion
The US EPA’s Handbook for Developing a Watershed Plan to Restore and
Protect Our Water (2005) defines structural practices as “a practice, such as a
stormwater basin or streambank fence, that requires construction, installation, and
maintenance.” For this study, the following structural alternatives and BMPs are
evaluated and considered:
· Restoration of Riparian Corridors
· Stabilization of Eroded Streambeds and Streambanks
· Grassed Waterways
· Water and Sediment Control Basins and Ponds
· Sediment and Nutrient Control Basin
· Gully/Grade Stabilization Structures
Non-Structural Alternatives and BMPs
Nutrient Management Plans are voluntary measures designed to minimize
nutrient losses from agricultural lands. Historically, the NRCS and SWCD has provided
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assistance with the development of nutrient management plans. The NRCS (2001)
defines nutrient management plans as “managing the amount, source, placement, form,
and timing of the application of nutrients and soil amendments.” The focus of nutrient
management plans is to increase the efficiency with which applied nutrients are utilized
by crops (US EPA, 2003). Strategically applying fertilizers and soil amendments to the
watershed reduces nutrient loads to Honey Creek and Lake Carlinville.
The University of Illinois at Urbana-Champaign (2005) has identified the following
steps in developing nutrient management plans:
· Assess the natural nutrient sources (soil reserves and legume contributions)
· Identify fields or areas within fields that require special nutrient management
precautions
· Assess nutrient needs for each field by crop
· Determine quantity of nutrients that will be available from organic sources,
such as manure or industrial or municipal wastes
· Allocate nutrients available from organic sources
· Calculate the amount of commercial fertilizer needed for each field
· Determine the ideal time and method of application
· Select nutrient sources that will be most effective and convenient for the
operation
Studies conducted by the U.S. Department of Agriculture have demonstrated that
average annual phosphorus application rates were reduced by 36 lbs/acre when
nutrient management practices were adopted (U.S. EPA, 2003). Nutrient management
is generally effective, but most phosphorus containing fertilizer is applied to the surface
of the soil and is subject to transport (NRCS, 2006). In an extensively cropped
watershed such as Lake Carlinville, the loss of even a small fraction of the fertilizer-applied
phosphorus can have a significant impact on water quality.
The U.S. EPA (2003) estimates that developing a nutrient management plan
varies from $6 to $20/acre. For the purposes of this study, a cost of $15 per acre was
used. These costs are often offset by the savings associated with using less fertilizer
and fuel. For example, the U.S. EPA (2003) reported that improved nutrient
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management on cornfields led to a savings of approximately $3.60/acre during a study
in Iowa.
Crop Rotations or utilizing cover crops keeps agricultural land under vegetative
cover year round or as much as possible. Crop rotation is another management
alternative method that can reduce erosion and subsequent soil and nutrient transport
within the watershed. As an added benefit, vegetative cover also increases water
infiltration and decreases runoff. Rotating crops reduces water and wind erosion and
can improve crop yields by recycling nutrients. This practice will ultimately reduce soil
and nutrient loadings to Honey Creek and Lake Carlinville.
Crop rotations include: pasture or hayland planting, cover crops, conservation
cover, and planting warm or cool season grasses. Cover crops include grasses,
legumes or small grains grown between regular grain crop production periods for the
purpose of protecting and improving the soil (on line Purdue, 1998). Legumes have an
added benefit of adding nitrogen to the soil to reduce the need for commercial fertilizers.
Conservation cover, a type of land cover, establishes and maintains perennial
vegetation on lands retired or removed from agricultural production. Conservation cover
can be a variety of different species depending on long term objectives of the land user
and the needs of target wildlife species. Conservation cover reduces soil erosion and
sedimentation, improves water quality by acting as a filter to remove chemicals and
other nutrients, and creates or enhances wildlife habitat (USDA-NRCS, 2005).
The following list published by the NRCS represents approximate costs required
to implement various crop rotations (NRCS, 2003).
Pasture and Hayland planting per acre $170.00
Fencing per linear foot $2.00
Cover Crops per acre $25.00
Conservation Cover per acre $70.00
Warm Season Grass per acre $188.00
Wildlife Habitat per acre $200.00
Conservation Tillage Practices include any tillage and planting system that
maintains at least 30 percent crop residue after planting and harvesting. Examples of
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conservation tillage include no till, ridge till, and mulch till. Advantages of conservation
tillage over conventional systems can include fuel and labor savings, lower machinery
investments and repair costs, and long-term benefits to soil structure and fertility
(USDA, 1996). Soil and nutrient load reductions are achievable through conservation
tillage, as soil erosion and transport are reduced. Conservation tillage practices are
defined by USDA (1996) as the following:
· No Till - The soil is left undisturbed from harvest to planting except for nutrient
injection. Planting or drilling is in a narrow seedbed or slot created by
coulters, row cleaner, disk openers, in-row chisels, or roto-tillers. No till
generally includes 50 percent or more residue after planting.
· Ridge Till - The soil is left undisturbed from harvest to planting except for
nutrient injection. Planting is in a seedbed prepared on ridges with sweeps,
disk openers, coulters, or row cleaners. Residue is left on the surface
between the ridges. Ridge till generally includes 30 to 50 percent residue
after planting.
· Mulch Till - The soil is disturbed before planting. Tillage tools, such as
chisels, field cultivators, disks, sweeps, or blades are used. Mulch till
generally includes 30 percent or more residue after planting.
Conservation tillage is an important tool used to reduce sheet and rill erosion
within agricultural fields. Using continuous no till methods can reduce soil loss by 75
percent over conventional methods. The NRCS (2003) recommends that row crops
grown on slopes greater than 5 percent (i.e., B slopes or greater) should be
continuously no tilled. Conservation tillage practices have been reported to reduce total
phosphorus loads by 45 percent (U.S. EPA, 2003). A wide range of costs has been
reported for conservation tillage practices, ranging from $12 per acre to $83 per acre
(1998 dollars) in capital dollars (U.S. EPA, 2003). For no till, the Illinois Agronomy
Handbook for Machinery and Labor lists costs that range from $36 to $66 per acre
(UIUC, 2005). For the purposes of this study, a median cost of $50 per acre was used
for conservation tillage. Many of the initial capital costs associated with conservation
tillage may be off set by reduced operating fuel costs (i.e., labor, lower machinery
investments and repair costs).
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Conservation Buffers include a wide array of BMPs: buffer strips, field borders,
filter strips, vegetative barriers, and riparian buffers. Ultimately, conservation buffers
reduce soil erosion on sloping ground and provide refuge and nesting cover for wildlife.
Buffers are optimized when they include a mixture of native warm-season grasses,
native cool-season grasses, and legumes (NRCS, 2003). Generally, field borders are
planted on the north and west edges of fields to serve as natural wind breaks and snow
fences. The NRCS recommends that field borders at a minimum be at least 30 feet
wide to provide erosion reduction and wildlife habitat benefits. It is recognized that one
of the biggest drawbacks for many farmers would be the loss of acreage for production.
However, in fields that border wood lands and riparian areas along Honey Creek, the
bushel per acre will likely be minimal, as the trees typically shade out and uptake most
of the available water. The cost to plant half cool-season and half warm-season
grasses with legumes is estimated at approximately $500 per acre (NRCS, 2003).
Inspecting and Upgrading Septic Systems is a practice that ensures
wastewater is properly disposed of and not transferred to the lake. Septic systems are
common in rural communities, where centralized wastewater treatment systems are not
economical. Most of the residences and facilities within the Lake Carlinville watershed
utilize septic systems to treat domestic wastewater from toilets, wash basins, bathtubs,
washing machines, and other water consumptive items. Due to their widespread use
and high volume discharges, septic systems have the potential to pollute groundwater,
lakes, and streams. Typical pollutants in household wastewater are nitrogen,
phosphorus, and disease causing bacteria and viruses (Center for Watershed
Protection, 2006). Unlike other non-stormwater discharges, septic systems are not
regulated under the EPA’s National Pollution Elimination Discharge System program
(NPDES) but are approved by local and state health departments.
While the Macoupin County Health Department oversees the installation of new
septic systems, inspections and routine maintenance on existing septic systems are
voluntary and are the responsibility of homeowners. The U.S. EPA (2001) recommends
that septic systems should be inspected every three years. Prior to new or renewal
lease agreements, the City of Carlinville requires that each lake site provide written
verification that the septic or holding tank system has been inspected and is in working
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order (personal communication Bellm, 2006). Routine inspections, maintenance, and
replacement/upgrades of septic and holding systems would help reduce pollutant loads
within the Lake Carlinville watershed. The estimated cost of a septic system inspection
ranges from $100 to $300 (personal communication, Bussman 2007).
Changing Landscaping Practices includes a variety of techniques that
specifically reduce the likelihood that excess sediment and nutrients could be
transferred to the lake. In areas that are adjacent to receiving waters, such as Honey
Creek or Lake Carlinville, improved landscape practices can help reduce erosion and
subsequent soil and nutrient loadings. Changes in landscaping practices can be
implemented at various levels within the community (i.e., leased lake lots and the City’s
maintenance department). Most of the occupants on Lake Carlinville currently mow the
grass down to the water’s edge. Allowing native vegetation to grow near the stream
banks and shorelines (especially on steep slopes) would create conservation buffers or
vegetated buffer strips that trap or reduce sediment and nutrient loadings in runoff.
Utilizing fertilizers with no phosphorus will also reduce loadings. These operation and
maintenance requirements could be included within the lake lease agreements. As an
added benefit, allowing vegetation to grow long near the lake may reduce maintenance
costs for the City. This alternative is an excellent way to preserve the lake at little to no
cost.
Livestock Exclusion consists of preventing livestock from accessing natural
waterways by installing fencing, stream crossings, and providing alternate watering
sources. Data within the Macoupin Creek Watershed Report (NRCS, 2003) suggest
that nearly a dozen livestock (i.e., cattle and hog) operations are present within the Lake
Carlinville watershed. Stream corridors in particular are places where livestock inhabit,
as these areas are generally highly productive, providing water and plenty of forage.
Unless carefully managed, livestock can over use waterways and create significant
disturbances. The main impact to waterways from livestock is loss of vegetative cover
from overgrazing, which accelerates streambank erosion. For larger livestock
operations, fecal material can increase nutrient and bacterial loads, which impairs
stream water quality and can also reduce dissolved oxygen levels (NRCS, 2003).
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Limiting livestock access to Honey Creek and other waterways within the Lake
Carlinville watershed would help to reduce streambank erosion and nutrient and
bacterial loadings within the watershed. Two alternatives have been suggested by the
NRCS (2003) to exclude livestock from waterways: installing an alternate watering
facility and fencing or installing fencing to limit creek access and constructing creek
crossings.
Option #1 - Alternate water facility and fencing
Costs: Water tanks/troughs $125.00 each
1.5-inch water lines & trenching $2.50 per foot
Woven wire fencing $2.00 per foot
Option #2 - Install fencing and limited crossings to access creek
Costs: Woven wire fencing $2.00 per foot
Limited crossing access $1,500 per structure
Structural Methods
Restoration of Riparian Corridors consists of re-establishing areas that were
previously forested and have been cleared or altered due to human activities. Riparian
corridors are ecosystems that border streams, lakes, and watercourses. Generally, they
contain three major elements: a stream channel, a floodplain, and a transitional area to
uplands. Riparian corridors provide critical functions such as the cycling of nutrients,
filtering contaminants from runoff, absorbing and gradually releasing floodwaters,
maintaining fish and wildlife habitats, recharging groundwater, and maintaining stream
flows (NRCS, 2003).
In The Upper Macoupin Creek - Watershed Restoration Action Strategy, the
NRCS stated that nearly two-thirds of the riparian corridors within the Macoupin Creek
watershed (which includes Lake Carlinville) had been cleared and were now used for
agriculture. Most of these farmed areas are located on steeper slopes, which have
increased sheet, rill, and gully erosion and subsequent nutrient and sediment loadings
to adjacent waterways. Restoring these forested natural buffer areas will help reduce
sediment and nutrient loading within the Lake Carlinville watershed. The NRCS (2003)
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estimates that the cost to restore riparian corridors to native vegetation is approximately
$500 per acre.
Silviculture Practices include a variety of activities aimed toward maintaining a
high quality forest. Specifically, selective tree thinning has been identified to modify the
canopy in heavily forested areas in the Lake Carlinville watershed. The NRCS (1996)
reported that the upland forests were comprised of white and red oak and shagbark
hickory, while bottomland forests included silver maple, sycamore, cottonwood,
American elm, and green ash. These historical accounts of the upland and bottomland
forests with the Lake Carlinville watershed will likely require forest management to
insure their longevity.
In general, oaks and hickories compete with faster growing maples and other
smaller, more shade tolerant species for sun light. As maples invade and mature, it
becomes increasingly difficult for preferred canopy species such as oaks and hickories
to become established. Selective tree removal or thinning can promote growth of
preferable species by removing less desirable, usually smaller trees. This process can
influence the growth and quality of the larger canopy layer trees and allow sun light to
reach the underlying herbaceous and shrub layers that serve to stabilize soil on steep
slopes. Selective tree thinning projects have been initiated by the Medford District
Bureau of Land Management (MDBLM) in the Elk Creek Watershed for an estimated
cost of $560 to $1000 per acre (MDBLM, 2003). This cost includes removing trees less
than eight inches in diameter to reach a 50 percent canopy cover, piling, and burning.
Other riparian restoration projects have been implemented along the Illinois River at a
cost of approximately $4000 per acre (MDBLM, 2007). Selective tree thinning and
management will insure that the forests will remain healthy and continue to reduce
erosion within the watershed for generations to come. Forest management will help
sustain the lower gross erosion and subsequent sediment and nutrient delivery rates
that are characteristic of forested land uses, although management activities within the
watershed should be carefully considered and planned in order to minimize erosion as
activities are completed.
Stabilization of Eroded Streambeds and Streambanks consists of installing
structural measures to prevent extreme erosion in unstable areas. Streambed and
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streambank erosion has been identified as a significant source of solids and nutrients
within the Lake Carlinville watershed (NRCS, 1996 and 2003). Sediment derived from
streambed and streambank erosion increases sediment and nutrient loadings within the
watershed that ultimately decrease the water quality and storage capacity of Lake
Carlinville. Reviewing the USGS topographic maps and aerial photography for the Lake
Carlinville watershed suggests that streambed and streambank erosion along the
approximate 12 miles of Honey Creek is a vast issue.
HDR | CWI concurs with the NRCS (2003) assessment that inventories and
surveys should be completed along Honey Creek to identify and prioritize eroded
streambeds and streambanks. Inventories and surveys can be completed by
conducting low-level helicopter flights using Geographic Information Systems (GIS)
referencing imbedded video footage of a stream channel, or by “ground-truthing,” where
specific sites of interest are field examined and verified. To identify and prioritize
eroded streambeds and streambanks along Honey Creek the costs would be
approximately $15,000 to $20,000. It should be noted that stream access to Honey
Creek is somewhat limited. Intermittent creek flows, steep riparian slopes, and a limited
number of roadways make entry into Honey Creek challenging. These physical
constraints may complicate stream bank surveys and subsequent stabilization attempts.
In addition, the lack of suitable access to Honey Creek will likely increase stream bank
stabilization unit costs.
While various methods can be utilized to stabilize eroded streambeds and
streambanks, the NRCS (2003) recommended rock riffle grade controls to address
streambed erosion (i.e., channel downcutting and channel widening). Rock riffle
controls consist of loose rock fills placed in the channel to restore a “riffle” and “pool”
sequence. Riffles are typically placed at intervals of one riffle for every 6 bankfull
widths. This riffle to pool sequence and spacing enables a stable stream to transport
the water and sediment from the watershed most efficiently. The approximate cost of
$100 per ton for RR-5 stone including materials, trucking, and placement was used for
estimation purposes. Riffle construction costs will vary according to stream height and
width. Streambank stabilization and enhancement can include installing riprap
revetments for stone-toe protection, planting deep root vegetation, and adding bendway
109
weirs and barbs. Estimates to design and construct rip-rap revetments are estimated at
$100 per linear foot, with an estimated one ton of rip-rap per linear foot of eroded
stream bank. The unit costs per linear foot of streambank stabilization may vary
depending on access to Honey Creek (i.e., limited access) and the severity of erosion
(HDR | CWI experience, 2007.)
Grassed Waterways can be very effective for preventing gully erosion. They
force storm water runoff to flow down the center of an established grass strip, while
minimizing soil exposure and subsequent erosion during the process. In addition to
preventing gully erosion, grass waterways can be effective filters that trap sediment and
nutrients. However, they can lose their effectiveness if too much sediment builds up in
the waterway. In order to maintain optimal effectiveness, grassed waterways should be
implemented with other practices such as conservation tillage and conservation buffers.
Grassed waterways cost approximately $1,800 per acre and have annual maintenance
costs of roughly $25 per acre for mowing and $300 per acre for burning (NRCS, 2003).
Water and Sediment Control Basins (WASCOBs), also referred to as dry
dams, are earth embankments constructed across a slope and a minor waterway to
form a sediment trap and water detention basin. They trap water and sediment runoff
from cropland and reduce gully erosion by controlling flows within the drainage area.
WASCOBs have several benefits including reducing waterway and gully erosion,
sediment trapping, reducing and managing on-site and downstream runoff, and
improving downstream water quality (NRCS, 2003). These structures tend to work best
when other BMPs such as conservation tillage and crop rotations are use concurrently.
For the purposes of this study, WASCOB structures are estimated at $2,500 each
(McCandless personal communication, 2007).
Ponds or small impoundments can be constructed along minor waterways and
ravines as an alternative to WASCOBs. Ponds trap sediment and nutrients and can
provide habitat and recreational opportunities. For the purposes of this study, ponds
construction of ponds is estimated to be approximately $50,000 per acre based on
previous HDR | CWI experience. This cost includes clearing, earth work, discharge
structure, riprap slope protection, and seeding.
110
Sediment and Nutrient Control Basins are designed to capture a large amount
of the sediment and nutrients in runoff during storm events. In 1996, the USDA-NRCS
published the Lake Carlinville Watershed Plan and Environmental Assessment. The
primary recommendation within the NRCS report was a wetland sediment detention
basin across the upper arm of Lake Carlinville along the main stem of Honey Creek.
The proposed control basin would have intercepted approximately 95 percent of the
drainage area from the Lake Carlinville watershed. The preliminary design was
completed by NRCS engineering and included a seven-foot high gabion structure
constructed across the entire width of the reservoir (approximately 500 feet). During
periods of average rainfall, water would pass through a conduit. High flows would be
temporarily impounded behind the gabion structure (allowing sediment and nutrients to
be deposited) before passing over the dam (NRCS, 1996 and 2002). NRCS
engineering estimated an annual average of three high flow events. Figure 30
illustrates the approximate location of the proposed NRCS dam and the extent of the
sediment and nutrient control basin.
In 1996, the NRCS calculated that the proposed sedimentation basin would have
an estimated 70 percent trapping efficiency and was designed to trap approximately 50
years worth of sediment (i.e., 341 acre-feet of sediment). The total project costs in 1996
were $554,600 with a $296,000 Federal share from a PL-566 grant and $258,600 as the
local share. The average annual costs were estimated at $56,300 and included
$12,200 for operation, maintenance, and replacements (NRCS, 1996 and 2002). The
proposed sedimentation basin was not constructed, possibly because flood easements
required for the project could not be obtained from private landowners (personal
communication Bellm, 2006).
HDR│CWI believes that the costs to design and construct the proposed
sedimentation basin will be considerably more than the 1996 amount of $554,600. At
an estimated annual inflation rate between 3% and 4%, the sedimentation basin could
cost as much as $840,000. In the current regulatory climate, additional permitting and
mitigation could be necessary that may not have been required in 1996. These
additional requirements would also increase the overall costs.
111
Gully/Grade Stabilization Structures are installed to prevent gully erosion by
controlling the grade in areas that have naturally or artificially formed a channel or are
likely to form a channel if not stabilized. They are typically necessary in areas that
receive concentrated runoff or have steep slopes, such as riparian areas adjacent to
Lake Carlinville. Several varieties of grade stabilization structures (i.e., stockade post
structures; post, weir, and brush structures; post-weir structures; and rock grade
stabilization structures) could be constructed to minimize gully erosion. For the
purposes of this study, a median cost for gully stabilization structure of $40 per linear
foot was used based on previous HDR | CWI experience.
Drainage Water Management is the practice of using water control structures in
a main, sub-main, or lateral field tile drainage system to vary the depth of the drainage
outlet. In this process the water table must rise above the outlet depth for drainage to
occur, which can be altered by a control structure. The depth of the control structure
can be raised or lowered depending on the season and conditions (Frankenberger et
al., 2006). Frankenberger (2006) and Evans et. al., 2003 suggest median load
reductions for total nitrogen to be approximately 45 percent. Reductions for solids and
total phosphorus are expected to be minor.
· The structures can be raised after harvest to limit drainage outflow and
reduce the delivery of nitrate to ditches and streams during the off-season.
· The structures can also be lowered in the early spring and again in the fall so
the drain can freely flow before field operations (i.e., planting and harvest)
occur.
· The structures can also be raised after planting and spring operation have
been completed to create a potential to store water for crops to utilize during
the midsummer (i.e., raises the water table).
The practice of drainage water management is only suitable on fields that need
drainage (e.g., the upper portion of Lake Carlinville watershed, where slopes are one
percent or less). These areas are shown in light green in Figure 3 (Part 1) and
represent a large portion of the watershed. One water control structure can typically
control from 10 to 20 acres. Studied have found reductions in annual nitrate load in
drain flow vary from 15 to 75 percent, depending on location, climate, soil type, and
112
cropping practice. The cost for water control structures varies from $500 to $2,000,
depending on height, size of drainage tile, structure design, and manufacturer.
Installation costs are typically about $200 per structure but can increase depending on
site-specific conditions. Assuming surface grades are flat enough for one structure per
20 acres, installation costs are expected to be approximately $100 per acre
(Frankenberger et al., 2006).
Urban land management can be important in watersheds that have a high
percentage of urban land use. Since urban land comprises only 1% of the Lake
Carlinville watershed, best management practices for urban land are not emphasized in
the Watershed Plan. For the small areas that may benefit from urban land
management, including the Lake Williamson community, the following practices could
be considered: street sweeping, erosion control plantings, infiltration structures,
retention basins, runoff controls, sediment filters, vegetative swales, storm water
management, and zoning.
Proposed Actions
Table 28 provides a summary of proposed lake and watershed management
alternatives for the entire watershed, as well as potential costs, load reductions, and
resources for financial and technical assistance. A combination of non-structural and
structural watershed management alternatives and BMPs should be implemented
throughout the watershed over the next ten years. Specific locations for BMPs are
proposed for the City and privately owned properties that were observed during the
study (Figure 30); however, general locations are targeted for BMPs throughout the
majority of the watershed that was not accessible during the study. A phased
implementation approach is recommended in which specific locations identified in this
report should be targeted for the first phase of implementation. The first phase should
be used as a tool to demonstrate implementation of various BMPs and promote
implementation of BMPs on privately owned land in the upper end of the watershed.
Once additional cooperating landowners are identified, specific locations for
implementation of additional BMPs can be identified and incorporated into the next
phase of implementation.
Range of Unit Costs Units Proposed
Sediment
(tons/yr)
Nitrogen
(lbs/yr)
Phosphorus
(lbs/yr)
Financial Assistance Technical Assistance
1. SPECIFIC RECOMMENDATIONS & MANAGEMENT PRACTICES FOR THE LAKE CARLINVILLE WATERSHED
A. SPECIFIC WATERSHED ALTERNATIVES - Action Item A Low High
City Property Conservation Tillage $45 to $55 per acre 75 Acres $3,375 $4,125 74.0 160.0 80.0 City, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Cover Crops $20 to $30 per acre 75 Acres $1,500 $1,875 118.0 261.0 131.0 City, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Nutrient Management Plans $15 to $20 per acre 75 Acres $1,125 $1,500 NA 39.2 3.2 City, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Inspect & Update Septic & Holding Tanks $100 to $300 Lake properties ** ** ** ** ** City & Homeowners Local Contractor
Modify Landscaping Practices ** Lake properties ** ** ** ** ** City, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Conservation Buffers $400 to $600 per acre 15 Acres $6,000 $9,000 64.0 210.0 113.0 City, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Water & Sediment Control Basins $2,000 to $3,000 each 5 Structures $10,000 $15,000 395.0 475.0 240.0 City, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Sediment & Nutrient Control Basin (1996 NRCS Design) $845,000 to $925,000* 1 Structure $845,000 $925,000 12,306.0 17,200.0 5,200.0 City, NRCS, SWCD, US EPA, & IL EPA HDR | CWI & NRCS
Gully/Grade Stabilization Structures $40 to $50 per linear foot 7,000 Linear feet $280,000 $350,000 756.0 1,519.0 756.0 City, US EPA, IL EPA, NRCS & SWCD HDR | CWI
Private Property Side-Channel Sediment & Nutrient Control Basin $50,000 to $60,000 per acre 5 Acres (17.5 Acre-Feet) $250,000 $300,000 253.0 344.0 104.0 City, landowner, US EPA, IL EPA, NRCS & SWCD HDR | CWI
Pond $50,000 to $55,000 per acre 1 Acre $50,000 $55,000 844.0 95.0 48.0 City, landowner, US EPA, IL EPA, NRCS & SWCD HDR | CWI, NRCS & SWCD
Water & Sediment Control Basin $2,000 to $3,000 each 1 Structure $2,000 $3,000 115.0 95.0 48.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Gully/Grade Stabilization Structures $40 to $50 per linear foot 800 Linear Feet $32,000 $40,000 48.0 95.0 48.0 City, landowner, US EPA, IL EPA, NRCS & SWCD HDR | CWI
Conservation Buffers $400 to $600 per acre 10 Acres $4,000 $6,000 551.0 110.0 55.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Conservation Tillage $45 to $55 per acre 60 Acres $2,700 $3,300 76.0 230.0 123.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Grassed Waterways $1,500 to $2,000 per acre 2.5 Acres $3,750 $5,000 32.0 60.0 32.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Subtotal $1,491,450 $1,718,800
B. SPECIFIC LAKE ALTERNATIVES - Action Items B, C, and D Low High
City Property Lake Shoreline Stabilization via Riprap Revetments† $75 to $85 per linear foot 4,000 to 5,000 linear feet $300,000 $425,000 525.0 1,049.0 525.0 City, US EPA & IL EPA HDR | CWI
Sediment Removal via Hydraulic Dredging † $6.25 to $7.00 per cubic yard 500,000 to 750,000 yd3 $3,125,000 $5,250,000 33,422.4 1,091,610.1 109,161.0 City, IL EPA HDR | CWI
Restructure Lake Fish Population $20,000 to $275,000 NA $20,000 $275,000 NA NA NA City & IL DNR IL DNR
Fish Habitat Structures $250 to $750 each 10 Structures $2,500 $7,500 NA NA NA City & IL DNR IL DNR
Subtotal $3,447,500 $5,957,500
C. OTHER RECOMMENDATIONS - Action Items E and F Low High
Watershed & Lake Coordinator(s) $10,000 to $20,000 per yr. (part time) NA $10,000 $20,000 NA NA NA City, US EPA HDR | CWI
Educational and Informational Programs $8,000 to $12,000 NA $8,000 $12,000 NA NA NA City, US EPA & IL EPA HDR | CWI
Survey Eroded Streambanks of Honey Creek $15,000 to $20,000 NA $15,000 $20,000 NA NA NA City, US EPA & IL EPA HDR | CWI
Monitoring Program (sampling & analysis) $13,000 to $20,000 NA $13,000 $20,000 NA NA NA City & US EPA HDR | CWI
IL EPA Post Implementation Report $40,000 to $60,000 NA $40,000 $60,000 NA NA NA City & US EPA HDR | CWI
Subtotal $86,000 $132,000
Total $5,024,950 $7,808,300
Range of Unit Costs Units Proposed
Sediment
(tons/yr)
Nitrogen
(lbs/yr)
Phosphorus
(lbs/yr)
Financial Assistance Technical Assistance
2. GENERAL RECOMMENDATIONS FOR THE LAKE CARLINVILLE WATERSHED - Action Item A Low High
Private Property Conservation Tillage - Mulch Till $40 to $50 per acre 500 Acres $20,000 $25,000 712.0 1,424.0 712.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Conservation Tillage - No Till $40 to $50 per acre 500 Acres $20,000 $25,000 1,482.0 3,160.0 1,580.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Crop Rotations $20 to $30 per acre 500 Acres $10,000 $15,000 1,127.0 2,323.0 1,162.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Septic & Holding Tank Inspect & Upgrade $100 to $300 Watershed properties ** ** ** ** ** City, landowner, US EPA, IL EPA, NRCS & SWCD Local Contractor
Changing Landscape Practices ** Watershed properties ** ** ** ** ** City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Water & Sediment Control Basins $2,000 to $3,000 each 20 Structures $40,000 $60,000 848.0 192.0 96.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Drainage Water Management $1,500 to $2,000 per acre 200 Acres $300,000 $400,000 184.0 4,950.0 360.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Silviculture Practices $1,000 to $4,000 per acre 50 Acres $50,000 $200,000 385.0 306.0 154.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Grassed Waterways $1,500 to $2,000 per acre 50 Acres $75,000 $100,000 1,050.0 2,150.0 1,050.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Nutrient Management Plans $15 to 20 per acre 500 Acres $7,500 $10,000 NA 262.0 22.3 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Pasture $150 to $200 per acre 200 Acres $30,000 $40,000 1,280.0 654.0 484.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Wildlife Habitat $180 to 220 per acre 200 Acres $36,000 $44,000 1,410.0 918.0 550.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Conservation Buffers $400 to $600 per acre 500 Acres $200,000 $300,000 636.0 1,889.0 1,013.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Livestock Exclusion $5,000 to $8,000 per area 4 Livestock Areas $20,000 $32,000 18.4 496.0 160.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Restoration of Riparian Corridors $400 to $600 per acre 50 Acres $20,000 $30,000 385.0 306.0 154.0 City, landowner, US EPA, IL EPA, NRCS & SWCD NRCS & SWCD
Stream Bed stabilization $5,000 to $7,500 per structure 10 Structures $50,000 $75,000 83.0 114.0 34.0 City, landowner, US EPA, IL EPA, NRCS & SWCD HDR | CWI
Stream Bank stabilization $100 to $110 per LF 2,000 LF $200,000 $220,000 454.0 908.0 454.0 City, landowner, US EPA, IL EPA, NRCS & SWCD HDR | CWI
Ponds $50,000 to $55,000 per acre 10 Ponds $500,000 $550,000 532.0 96.0 48.0 City, landowner, US EPA, IL EPA, NRCS & SWCD HDR | CWI, NRCS & SWCD
Gully/Grade Stabilization Structures $40 to $50 per linear foot 5,000 LF $200,000 $250,000 795.0 1,595.0 795.0 City, landowner, US EPA, IL EPA, NRCS & SWCD HDR | CWI
Total $1,778,500 $2,376,000
* Cost was increased by an annual inflation rate between 3% to 4% above the 1996 NRCS preliminary design estimated cost of $554,600.
** Costs & load reductions vary depending on work required.
*** Load reduction estimates are not additive. Additional load reduction information is included in Appendix F.
† Including engineering costs
Range of Estimated Costs
Range of Estimated Costs
Table 28. Lake Carlinville Watershed Plan & Implementation Summary
Estimated Load Reductions *** Implementation Estimated Costs Assistance
Recommended Actions & Management Practices
Watershed Management Practices
114
Back page of table due to 11 x 17 size
Limits of Maximum Flooding
Sediment and Nutrient Control Basin
NRCS Design (1996)
0 650 1,300 2,600 3,900 5,200
Feet ±
Legend
Gully Stabilization
WASCB
Pond
Pond Watershed
Conservation Buffer
Grassed Waterways
Figure 30. Approximate Locations of Proposed Watershed BMPs
Lake Carlinville Watershed
USGS Topographic Map (1974)
116
Recommendations for City-owned property adjacent to Lake Carlinville
As the owner and steward of Lake Carlinville, the City of Carlinville should take
the lead by implementing watershed management alternatives and BMPs on City-owned
land in the lower end of the watershed. This action would send a message to
the community that the City is serious about the restoration of Lake Carlinville and its
watershed. To facilitate implementation of projects on City-owned land, potential project
locations were identified for the following non-structural and structural watershed
management alternatives:
· the 1996 NRCS sediment and nutrient control basin,
· gully/grade stabilization structures - approx. 7,000 linear feet,
· agricultural land management practices on approx. 75 acres of fields,
· water and sediment control basins (5 structures),
· inspecting and upgrading septic and holding tanks on lake properties, and
· modifying landscaping practices on lake properties.
Recommendations for Privately-owned properties near Lake Carlinville
HDR | CWI toured a privately owned property located along the east end of Lake
Carlinville. Along the east side of Honey Creek is a 5 to 6 acre area (southeast corner
of Section 11 of T9N and R7W) that could be developed as a side-channel sediment
and nutrient control basin and enhanced to create a wildlife habitat area for water fowl.
Essentially, the basin would be designed to retain flood waters and trap sediment and
nutrients. A sketch of the proposed pond location is illustrated in Figure 30.
HDR | CWI visited a second private property where several watershed BMPs,
such as dry dams and conservation tillage practices, were already implemented.
Several potential pond locations along ravines north of an unnamed tributary of Honey
Creek were evaluated (southwest corner of Section 11 of T9N and R7W). A potential
outline of the proposed pond and associated watershed is illustrated in Figure 30. The
representative for the private landowner stated that the pond(s) could serve as a
watering source for the livestock. Separate from providing an alternate watering source
for cattle, the pond would provide load reductions for the watershed by trapping
sediment and nutrients generated from runoff and gully erosion.
117
HDR | CWI met a third private landowner (northwest corner of Section 14 of T9N
and R7W) that had constructed a pond in which several algal blooms had occurred
shortly after filling the pond. The pond was surrounded by sloping agricultural fields
with few to no conservation buffers, filters strips, or grassed waterways. Adding these
watershed features, as a buffer between the pond and the agricultural fields, would
enhance the pond and wildlife (Figure 30). As an added benefit, these structures, along
with improved farming practices (i.e., conservation tillage), would reduce loadings to the
small pond and the larger Lake Carlinville watershed. Since this pond drains to the
lake, direct benefits for to Lake Carlinville would result from these actions.
General recommendations for the Lake Carlinville watershed
Aside from the aforementioned private landowners, public participation during
this study was minimal. Restricted access to private property made evaluating existing
conditions for site-specific watershed management projects challenging; however,
HDR|CWI was able to conduct a tour of the Lake Carlinville watershed from public
roadways (Figure 31). In addition to field surveys, remote sensing with GIS, aerial
photography, topographic mapping, land cover types, and soil surveys was used to
evaluate the Lake Carlinville watershed. Despite the watershed information that was
analyzed, site-specific watershed projects were not proposed, as it may be difficult to
obtain land easements that are required to implement watershed management
practices. It is important to note that watershed BMPs located on privately owned lands
can be achieved and should be pursued. Given their local presence and knowledge,
the local NRCS and SWCD offices will be critical allies in these endeavors. A
watershed coordinator (see Action Item F) can also help with this task.
Although specific locations for BMP implementation throughout the entire
watershed are not identified in this report, data that can be used to target troublesome
areas are included. For example, Figure 31 shows all the lakes and streams throughout
the watershed. During the watershed survey, streambank erosion was noted at almost
every road and stream crossing. These areas would be good candidates for
streambank stabilization. Good land management practices are most important in
areas adjacent to any water body, especially those areas with highly erodable land
118
(HEL) (Figure 32). Figure 32 also shows areas with steep slopes that are designated
for agricultural use. These areas are highly susceptible to sediment and nutrient
transfer to the adjacent water body. Figures 3 and 7 (pages 21 and 31 in Part 1) can be
used to further target locations and types of BMPs to be implemented. Forest
management, gully stabilization, and streambank stabilization should be considered for
red areas in Figure 3, which represent very steep slopes. Nutrient management plans,
crop rotations, and conservation tillage practices should be considered for all
agricultural areas shown in Figure 7.
Although general areas for implementing BMPs can be identified using methods
discussed previously, it is important to note that some of these areas may already have
BMPs implemented. Given the limited public participation and land access, it was not
possible to distinguish areas that currently have BMPs in place. As a result, a general
approach was taken for proposing management alternatives within the watershed. Cost
estimates and load reductions were developed and calculated for the watershed
management alternatives listed below with the assumption that those management
measures would be implemented over time as cooperating landowners are identified.
Watershed management alternatives and BMPs:
· Nutrient Management Plans - 500 acres
· Crop Rotations - 900 acres
· Conservation Tillage Practices - 1,000 acres
· Conservation Buffers - 500 acres
· Inspect and Upgrade Septic Systems
· Changing Landscaping Practices
· Livestock Exclusion - 4 livestock facilities
· Restoration of Riparian Corridors - 50 acres
· Silviculture Practices – 50 acres
· Stabilize Eroded Streambeds (10 structures) & Streambanks (2,000 linear ft)
· Grassed Waterways - 50 acres
· Water and Sediment Control Basins and Ponds - 20 structures and 10 Ponds
· Gully/Grade Stabilization Structures - 5,000 linear feet
· Drainage Water Management – 200 acres
Figure 31. Route of General Watershed Survey
Macoupin 0 2,000 4,000 8,000 12,000 16,000 County, Illinois
Feet ± Survey Route
Watershed Boundary
General Watershed
Location
1:100,000 USGS Topographic Map (1974)
0 4,100 2,050 8,200 12,300 16,400
Feet ± Figure 32. Potential Focus Areas for Watershed BMPs
Lake Carlinville Watershed
2005 DOQQ Aerial Photograph
Watershed boundary
Ag land with C or greater slopes
Highly erodable land
121
Action Item B. Remove Accumulated Sediment from the Lake
Alternative Actions
According to the 2006 accumulated sediment volume as discussed in Part 1, an
estimated 1,425,009 cubic yards of sediment have been deposited over the 67-year
history of the lake. This estimated volume of accumulated sediment suggests that an
average of approximately 21,269 cubic yards of sediment have been deposited on
annual basis. The major alternatives for removing sediment in Lake Carlinville include
extended water level drawdown, mechanical dredging, and hydraulic dredging.
a. Lake Water Level Drawdown and Compaction
Lowering the water level and allowing the sediment to dry and consolidate is an
alternative for restoring lost water depths in some lakes. However, this treatment
alternative is generally a poor solution when excessive sediment deposits are present.
In order to assure optimum drying and compaction, the water level would have to be
substantially lowered for a sufficient period of time. According to a study completed by
Fox et al. (1977), approximately 180 days of exposure to drying conditions would
produce a sediment consolidation ranging from 7 to 50 percent, with water losses
ranging from 40 to 50 percent. It is anticipated that the sediment found in the upper
portion of Lake Carlinville would fall in the median range, and would thus be expected to
consolidate approximately 25 percent.
In order to effectively reduce sediment volume in the upper end of Lake
Carlinville, water levels would have to be lowered significantly. This is not possible due
to the reservoir’s relatively linear morphology and hydrologic regime. Furthermore, a
drawdown extended well into the spring or even into the summer months would be
nearly impossible to implement because of the extremely large watershed drainage
area from Honey Creek and its tributaries. If it were possible, an extended drawdown
may have many negative impacts to the public water supply, aquatic community and the
recreational use of the lake. Due to these limitations, an extended drawdown and
compaction would not be the best option to address the accumulated sediment at Lake
Carlinville.
122
b. Mechanical Dredging
There are several methods of mechanical dredging or excavation presently
available. The lake can either be dredged at normal pool with a dragline, or the water
level could be lowered enough to allow low ground pressure excavation equipment into
the dry lakebed. There are several advantages to dry lakebed excavation as compared
to hydraulic or dragline dredging, such as the elimination of excessive turbidity or
resuspended solids, and a smaller quantity of material to remove due to consolidation
and compaction. However, there are many disadvantages and problems that could be
encountered. The length of time required for the sediment to dewater and consolidate
sufficiently enough to support excavation equipment may take longer than expected,
especially if frequent rainfall events occur. Although this method can sometimes be
accomplished at selected areas in the shallow upper ends of a lake, it is not a feasible
option for this lake since the Lake Carlinville watershed drains an extremely large area
and would likely cause flooding problems within the dredging area.
Another method of mechanical dredging could be accomplished with a dragline
while the lake water level is at normal pool. This is accomplished by extending
excavating equipment from shore, or by mounting the equipment on a barge. This
method is more practical for smaller lakes or when a large quantity of rocks or debris is
anticipated. Removal of accumulated lake sediment in this manner is inefficient and
can leave high percentages of material behind. Transportation and storage of the
sediment is also very inefficient and labor intensive since it must be handled several
times. Once the sediment is removed from the lake, it must be placed on a barge or a
truck and transported to the storage area. This repeated handling is generally not cost
effective and can result in sediment losses during transfer. Equipment access for the
removal and placement of dredged sediment would also have a negative impact on the
lake shoreline. Therefore, mechanical dredging with a dragline would not be considered
a feasible sediment removal method for Lake Carlinville.
c. Hydraulic Dredging
Hydraulic dredging involves a centrifugal pump mounted on a pontoon or hull,
which uses suction to pull the loose sediment off the bottom and pump it through a
polyethylene pipeline to a sediment retention area. Generally, a cutterhead is added to
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the intake of the suction line in order to loosen the accumulated or native sediment for
easy transport and discharge. A slurry of sediment and water, generally ranging
between 10 and 15 percent solids (by weight), can be pumped for distances as much as
10,000 to 15,000 feet or more with the use of booster pump(s). The efficiently pumped
sediment slurry must be discharged into a suitably constructed earthen dike-walled
containment area with adequate storage capacity. The sediment containment or
retention area must be properly designed to allow sufficient retention time for the
sediment particles to settle throughout the project, and allow the clear decant or effluent
water to flow through the outlet structure back to the lake.
One of the advantages of hydraulic dredging is the efficiency of sediment
handling. The removal, transport, and deposition are performed in one operation, which
minimizes expenses and potential sediment losses during transport. Another
advantage is that the lake does not have to be drained, and most areas can remain
open for recreation and public use. Most hydraulic dredges are considered portable
and are easily moved from one site to another. They are extremely versatile and are
capable of covering large areas of the lake by maneuvering with their spud anchorage
system and moving the discharge pipeline when necessary.
Proposed Actions
The proposed alternative for removing accumulated sediment from the upper end
and select bays of Lake Carlinville is hydraulic dredging. Table 28 includes a range of
estimated costs, estimated load reductions, and technical and financial assistance
requirements for sediment removal via hydraulic dredging. Prioritizing dredging areas
to target the more impacted shallow areas is critical to reducing the total dredging
volume, as it provides a more cost-effective alternative than removing all of the
accumulated material from the entire lake.
The most critical dredging locations include segments #6 through #15 from the
sedimentation survey (see Figure 24 in Part 1), where 49 percent of the lake’s original
storage capacity has been lost in the upper end of the lake. The total estimated
sediment volume in these prioritized locations is approximately 686,910 cubic yards.
Additional sediment removal is recommended in the deep basin area located east of the
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water supply intake; however, specific volumes cannot be estimated without a sediment
survey that targets that area. During the engineering design phase, a detailed and
updated sedimentation survey should be completed prior to bidding and
implementation. Strategically removing as much accumulated sediment as practical
from within this critical area of the lake will help restore lake water quality by removing
deposited materials and an internal nutrient source. In addition, water depths and
storage capacity can be restored in the upper end of the lake. The estimated quantity of
accumulated sediment in the upper end of the lake is significant enough that funding
availability will likely dictate the quantity of material that is ultimately dredged.
Therefore, Table 29 lists three options with varying opinions of cost have that have been
developed following a “good, better, and best” format to illustrate hydraulic dredging
possibilities for Lake Carlinville.
Table 29. Lake Sediment Removal Options and Probable Costs
Option Option 1 Option 2 Option 3
Dredging Area (Segments)* 6 through 15 7 through 15 9 through 15
Approx. Cubic Yards Removed 686,910 495,146 226,723
Sediment Retention Site Costs $686,910 $495,146 $340,084
Dredging Costs (incl. mobilization) $2,747,640 $2,228,157 $1,133,615
Subtotal $3,434,550 $2,723,303 $1,473,699
10% Estimating & Construction
Contingency $343,455 $272,330 $147,370
15% Engineering & Permitting $566,701 $408,495 $221,055
Total $4,344,706 $3,404,128 $1,842,124
*Variations in dredging areas may include selective deepening with in the area near the
dam and water intake.
For the purpose of this report, sediment removal Option #2 (i.e., 495,146 cubic
yards) is the minimum dredging volume recommended for Lake Carlinville. In the upper
portions of the lake, a maximum dredge cut depth of 8 to 10 feet or at least to the hard,
original bottom (which ever comes first) is recommended. This maximum cut depth will
minimize sediment resuspension post-dredging, which will in turn increase recreational
access, improve water quality and clarity, extend the useful lifespan from the project,
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and provide a long-term benefit to the lake. The removal of a minimum of 495,146
cubic yards of accumulated sediment would restore nearly 13 percent of the lake’s
original-1939 volume. Once removed, the volume that was once occupied by sediment
would provide additional lake water storage capacity. Using a conversion rate where
one cubic yard occupies nearly 202 gallons of water, removing this volume would
essentially provide 100,019,492 gallons of additional storage capacity. The City of
Carlinville has a peak daily water demand of approximately 1.45 MGD (Shaw personal
communication, 2006), which translates to an average of 44 million gallons per month.
Removing 495,146 cubic yards from Lake Carlinville would equate to more than a two-month
water supply for the City. This added storage capacity would be invaluable
during drought conditions.
If hydraulic dredging takes place, land will be required for the construction of a
retention facility that will store and dewater dredged sediment. The dredged sediment
can be beneficially reused as fertile agricultural soil and/or fill, thus maintaining the
value of the land. The amount of land required for this facility is directly proportional to
the quantity of sediment that is dredged. For recommended sediment removal Option
#2, it is estimated that approximately 17 to 25 hectares (42.0 to 61.8 acres) will be
required for a suitable retention and dewatering site. The largest dredge quantity
proposed (Option #1) would typically require between 24 to 36 hectares (59.3 to 89.0
acres) and the smallest dredge quantity proposed (Option #3) would require between
7.5 to 11.5 hectares (18.5 to 28.4 acres). The retention and dewatering site(s) should
be located within the watershed so that water can drain back into the lake. Further
evaluation and analysis will be required to find a suitable retention site location. Costs
for the land required for the retention site are not included with the opinions of probable
costs listed above. It is important to note that if multiple small sites are required, costs
will be higher than those listed. An existing pond located immediately south of the lake
was utilized for storing a small, undetermined volume of dredged material during the
1970s. This pond may be suitable for the recommended dredging project depending on
space availability and the extent of physical modifications necessary. In addition, an
existing agricultural field adjacent to this City owned pond may be suitable for
construction of a sediment storage and dewatering facility.
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Costs may also be higher if polymers or flocculants are necessary to accelerate
settling within the settling basin. The presence of excessive sodium within the Piasa
soils of the Herrick-Piasa-Virden soil association of the Lake Carlinville watershed may
impact the lake’s turbidity by allowing fine clay colloidal particles to remain in
suspension in the lake’s water column. This phenomenon, if present, will likely require
the use of a polymer or floccing agent to treat and reduce the effluent discharge
suspended solids concentrations in order to meet the Illinois EPA effluent water quality
standards. The addition of a floccing agent for effluent treatment will impact dredging
unit costs.
Action Item C. Stabilize and Protect Eroded Lake Shoreline Areas
Alternative Actions
Many products have been developed to control shoreline erosion and older
methods have been improved. The following were considered when deciding the best
approach for stabilizing the Lake Carlinville shorelines: riprap (both crushed stone and
rounded glacial stone) with bedding stone or filter fabric, erosion mats, plastic and
natural geowebs, gabions, railroad ties, interlocking concrete blocks, and natural
vegetative stabilization. Vegetative covering can provide protection by reducing wave
action and by binding the soil with roots. In addition to the erosion control benefits,
vegetative stabilization methods have the ability to absorb and assimilate nutrients from
runoff and, once established, require little or no maintenance since plants reproduce
and often spread naturally. For the correct application, these more natural stabilization
measures are aesthetically pleasing, provide habitat, and can be cost effective.
For slightly eroded areas with gently sloping littoral zones and no large direct
wave action, plant species such as prairie cord grass (Spartina pectinata) can be used.
Prairie cord grass is an emergent, herbaceous perennial that is native to North America
and has been proven to be excellent for erosion control with dense beds and deep root
systems, up to 2 ft. into the ground. The species is often found near water and wet
areas, does well in poor soils, and tolerates seasonal flooding. The plant can spread
aggressively, up to two feet per year (Michigan State University Extension, 1999).
Prairie cord grass plugs can be planted within sand bags (approximately 2 ft. long by 1
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ft. wide each) or within biodegradable fiber rolls and placed across the toe of the eroded
bank. The sand bags would provide immediate shoreline protection along with a
medium to hold the plantings in place until they could get established and rooted into
the shoreline. This natural form of shoreline stabilization would establish native plants
for erosion control and enhance habitat for wildlife (Erosion Control, 2000).
Riprap is another shoreline stabilization alternative that has proven to be very
effective for reducing and preventing erosion. Riprap with underlying geotextile filter
fabric would be ideal to address the moderately (3 to 8 ft. bank heights) and severely
(>8 ft. bank heights) eroded banks of Lake Carlinville. The advantages of riprap include
its reliable longevity, ease of installation and relatively inexpensive cost over large
areas. All riprap should be installed using either filter stone or filter fabric to prevent
washout from behind the installed riprap (Figure 33).
Figure 33. Examples of Riprap Shoreline Protection
Shoreline Revetment Offshore Breakwater
Proposed Actions
As a result of the shoreline erosion survey, the following shoreline stabilization
recommendations have been developed. Riprap and filter fabric should be used for
moderately and severely eroded shoreline and should be placed via barge or
mechanical riprap boat along the undercut bank of the shoreline two (2) feet below and
two (2) feet above normal pool (spillway elevation) at a 2 to 1 slope. When possible,
bare areas above the riprap should be graded to a 3 to 1 horizontal to vertical slope and
seeded. However, the eroded shoreline at Lake Carlinville is typically bordered by
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wooded growth at or near the shoreline and flattening the slope of the shoreline may be
difficult or impractical in most cases. Once the toe of the slope is protected from further
undercutting by structural methods, the eroded slope will gradually slough until a state
of equilibrium is reached. The estimated base cost of shoreline stabilization using
gradation RR4 broken limestone riprap is approximately $60 per linear foot, plus
allowances for contingencies, engineering, and permitting.
For areas of shoreline with gentle slopes and shallow littoral areas that have
been categorized as having slight bank erosion, emergent vegetation (i.e., prairie cord
grass or other native emergent aquatic plants) with sandbags could be used in order to
minimize wave action on shore and protect eroded banks from further undercutting.
The estimated cost of implementing vegetative plantings for erosion control and
shoreline stabilization is $20 per linear foot.
The current lengths of shoreline erosion within Lake Carlinville may be too large
to be addressed simultaneously. Therefore, shoreline stabilization projects should be
prioritized and completed based on the level of need in a series of phases. Subsequent
shoreline surveys are recommended to monitor and prioritize further lake shoreline
erosion. This approach will more effectively utilize available funding from grants and
cost-share sources to target the severely and moderately eroding shoreline areas that
are most susceptible to erosion by being exposed to waves generated by prevailing
winds. The prioritized areas should include moderate and severe erosion areas that are
most susceptible to additional erosion. All of the severely eroded shoreline (1,118 lineal
feet) and approximately half of the moderately eroded shoreline (2,122 lineal feet)
should be stabilized in the first phase. The stabilization of moderately eroded shoreline
shall be prioritized according to severity of undercutting and exposure to maximum wind
fetches and wave action. For select slightly eroded areas, vegetative plantings
(approximately 1,000 linear feet) are suggested.
Shoreline stabilization work on this scale will require a Joint Application Permit
from the Army Corps of Engineers (COE), the Illinois EPA, and the Illinois Department
of Natural Resources (IL DNR), particularly for riprap placed as fill material beneath the
normal water level. The benefits of shoreline stabilization would include reduced
sediment and nutrient loading, reduced turbidity, expanded shoreline habitat, improved
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aesthetic appearance, and prevention of further loss of valuable shoreline. Table 28
includes a range of estimated costs, estimated load reductions, and technical and
financial assistance requirements for lake shoreline stabilization.
Other Alternatives to Improve Water Quality
Alternative Actions
The primary alternatives for improving water clarity and restoring a more
balanced aquatic vegetation population include reducing solid and nutrient loadings
from the watershed on a continuous basis, altering nutrient availability, restructuring the
algae population so that blue-greens are not dominant, and reducing the amount of
suspended sediment and nutrients entering the lake during significant storm events.
Nutrients such as phosphorus and nitrogen can be controlled and reduced in many
ways such as: implementing best management practices in the watershed and the
construction of an in-lake sediment and nutrient control basin (Action Item A);
minimizing internal nutrient regeneration and sediment resuspension occurrences via
hydraulic dredging or re-establishing a rooted aquatic macrophyte community (Action
Item B); and the stabilization of eroded shoreline (Action Item C). Action items A, B,
and C were identified as the best strategies for improving water quality; however,
additional alternatives were considered and are discussed below.
Other potential alternatives for reducing nutrient concentrations include nutrient
diversion, dilution and flushing, discharge of hypolimnetic water, phosphorus
inactivation/precipitation, and artificial circulation. Due to the lake’s linear morphometry
and the hydrologic features of its extensive watershed, it would be technically unfeasible
and expensive to implement a diversion or flow routing system for the control of
nutrients. Dilution and flushing has been shown to be effective at reducing the
concentration of nutrients in the water column by adding “nutrient poor” water. Flushing
reduces algal biomass by increasing the loss rate of cells. However, dilution and
flushing are not considered acceptable alternatives for Lake Carlinville due to the lack of
suitable groundwater resources. Hypolimnetic discharges are normally not a feasible
solution for reservoirs, since anoxic conditions typically occur during the summer
months when water conservation is critical due to lack of precipitation and excessive
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water loss from evaporation. In addition, the release of anoxic waters to Honey Creek
from Lake Carlinville would have negative impacts on the biota within the creek/stream.
Phosphorus precipitation and inactivation are techniques used to lower the
concentration of phosphorus in the water column by either precipitating it out or
preventing its release from sediments. Aluminum sulfate (alum) can be added to the
lake surface in order to precipitate the phosphorus to the lake bottom. Additional alum
can be added to form a barrier in order to prevent or minimize phosphorus release from
the sediment during anoxic conditions. Properly applied alum treatments can result in
relatively long-term reductions of phosphorus in lakes where inflowing sources of
phosphorus have been sufficiently controlled and the resuspension of bottom sediments
is minimal but these issues are a concern for Lake Carlinville. The cost of alum
treatments typically ranges from $2,475 to $3,700 per hectare ($1,000 to $1,500 per
acre). Since the total surface area of Lake Carlinville is approximately 168 acres, the
cost for a whole lake alum treatment would range from $168,000 to $252,000 for a
single treatment. However, the lake’s expansive drainage area will continue to produce
significant sediment and nutrient loadings and the lake’s linear morphometry and rapid
hydraulic residence time would also limit the effectiveness of alum treatments.
Therefore, it appears highly unlikely that alum would be a suitable long-term alternative
for controlling phosphorus concentrations within Lake Carlinville.
Artificial aeration or destratification of lakes during the summer thermal
stratification period is a practice commonly used to improve water quality conditions
(i.e., increase dissolved oxygen concentrations). The primary improvements in water
quality that may be attained as a result of artificial aeration or destratification are
reduced nutrient loading from bottom sediments, reduced blue-green algal dominance
leading to a more desirable and diverse algal population, improved ecological diversity,
and increased oxygen levels and chemical oxidation of substances in the entire water
column.
The two primary methods of lake aeration/destratification include artificial
circulation and hypolimnetic aeration. Any system that is designed to mix or circulate
the lake or provide aeration without maintaining the normal thermal structure is
classified as an artificial circulation technique. Systems within this category include
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compressed air and/or mechanical devices capable of lifting anoxic hypolimnetic water
and circulating oxic surface waters in order to evenly distribute oxygenated water
throughout the lake. A compressed air system is typically used to initiate rising air
bubbles sufficient to reach the surface and flow out horizontally. The cold, dense water
eventually sinks to a level of equal density and eventually establishes a whole lake
mixing, if the system is sufficiently sized and designed. Hypolimnetic aeration is a
method of providing dissolved oxygen to the bottom waters of a lake without disrupting
the normal pattern of thermal stratification, which is typically reserved for deepwater
lakes. For Lake Carlinville, artificial circulation would be a suitable alternative to
improve lake water quality and to restructure the algal population.
Based on findings of Lorenzen and Fast (1977), a suitable system for the
approximately 50 acres near Site #1 and the public water supply intake at Lake
Carlinville should be capable of providing compressed air in the range of 32.5 to 65
CFM. Thus, an air injection (diffuser) system is a viable option for Lake Carlinville. The
system includes an on-shore air compressor that delivers air through lines connected to
diffusers located near the bottom of the lake. The rising air bubbles cause water in the
hypolimnion (cold, bottom layer) to rise into the epilimnion (warm, surface water layer).
As this occurs, the colder hypolimnetic water reaches the surface and mixes with the
warmer epilimnetic water. If the aeration system is adequately designed, the process
continues and ultimately mixes the metalimnion (layer between epilimnion and
hypolimnion) with the epilimnion and hypolimnion. Eventually, the dissolved oxygen
and temperature profile are nearly equal throughout the lake. Potential advantages and
disadvantages to operation of an artifical circulation system are listed below (reported
by Kothandaraman and Evans, 1983).
Potential advantages include:
1. Increased oxygen concentrations at the sediment/water interface can significantly
reduce the rate of nutrients (i.e., phosphorus) released from the sediment.
2. Benthic flora and fauna populations are typically more diverse and abundant
under well-oxygenated conditions, which can impart better food supplies for
game/sport fish species.
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3. A shift in algal populations may occur with a decrease in undesirable blue-green
species. This is partly a result of lowering the water temperatures; blue-green
algae are most tolerant of high surface water temperatures.
4. Oxidation of reduced organic and inorganic materials occurs. This is particularly
advantageous to water supply lakes because taste, odor and color problems
caused by iron, manganese, and hydrogen sulfide are minimized.
5. Evaporation rates can be reduced during summer months as a result of lower
surface water temperatures.
6. Artificial destratification often results in increased water clarity.
7. Maintaining a sufficient dissolved oxygen level under ice cover may reduce
occurrence of wintertime fish kills.
Potential disadvantages include:
1. An increased heat budget can be caused in the lake that slightly lowers the
temperature of the upper waters, whereas deep waters may be warmer by as
much as 15o to 20oC, approximately the same temperature as the surface.
2. There may be a temporary increase in water turbidity resulting from the
resuspension of bottom sediments.
3. Most investigations have resulted in a reduction of blue-green algae, but in some
instances, there was little or no effect.
4. The oxygen demand of resuspended sediments may result in low dissolved
oxygen concentrations, at least temporarily, that may be harmful to the fish.
5. Aeration may cause supersaturation of nitrogen gas, creating a potential danger
for fish from gas bubble disease.
Proposed Actions
Internal regeneration of phosphorus and nitrogen within Lake Carlinville is
estimated to be a relatively minor component of the overall nutrient budgets, as the lake
does not typically stratify for extended periods (due to the relatively shallow water
depths of the lake). In addition, the lake is periodically mixed as a result of prevailing
winds and the large volumes of runoff that flow into the relatively linear (i.e., riverine)
lake from a large drainage area. This flow pattern during normal summer weather
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conditions mixes the water within deeper portions of the reservoir and helps to limit the
internal release of nutrients by maintaining oxygenated conditions near the bottom for
most of the year. The exception to this periodic mixing may occur during exceptionally
dry seasons. Considering these conditions, installation of an aeration system within the
lower portion of Lake Carlinville would only be recommended in the event that
accumulated sediments are removed near the water supply intake and if water quality
improvements are not seen as a result of implementing Action Items A, B, and C. Given
the known accumulated sediment levels near the dam, spillway, and public water supply
intake, installing an aeration system prior to sediment removal could exacerbate
sediment re-suspension, which could subsequently increase lake algal blooms and
taste and odor issues within the public water supply.
A lake aeration system could potentially increase oxygen levels (reducing
seasonal hypolimnetic anoxia) and reduce the dominance of blue-green algae to allow
for a more diverse and desirable algal population, but is not considered a high priority at
this time. Increased dissolved oxygen concentrations within the lower portion of the
lake should improve lake water quality as fewer internal nutrients and taste and odor
compounds are generated. Improved water quality and fewer taste and odor issues
should benefit the public water supply. However, seasonal hypolimnetic anoxia does
not appear to be a prolonged issue based on Phase 1 water quality data. It is possible
that similar benefits may be achieved by implementing the previously mentioned action
items. If aeration is considered in the future, a compressed air destratification system is
recommended for approximately 50 acres near the water supply intake structure of Lake
Carlinville. The system includes weighted air hoses and high efficiency diffusers with a
well-ventilated and sound proofed air compressor house. This type of system, including
engineering design, has an estimated cost of $80,000 to $100,000 installed.
Objective #2: Enhance Lake Aesthetics & Recreational Opportunities
As the previous action items are addressed, lake aesthetics and recreational
opportunities will drastically improve; however, additional actions can be taken to further
improve the fish population in Lake Carlinville. Similar to the combination of actions to
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address Objective 1, the following actions items were identified to enhance the
aesthetics and recreational opportunities at Lake Carlinville.
A. Reduce the Amount of Sediment and Nutrients Entering the Lake
B. Remove Accumulated Sediment from the Lake
C. Stabilize and Protect Eroded Lake Shoreline Areas
D. Restructure Existing Fish Population
Action Item D. Restructure Existing Fish Population
Alternative Actions
IL DNR fisheries staff has made suggestions to remove accumulated silt from the
upper end of the lake and then restructure the fish population (Pontnack personal
communication, 2006). Attempting to restructure the existing fish population without
implementing the previous objectives will likely have limited results. Therefore, any
attempts at restructuring the fish population should be made after the following
conditions are addressed.
· Reduce delivery of excess sediment and nutrient loads to the lake in order to
improve water quality and subsequently improve fish habitat and spawning
opportunities (Action Item A);
· Remove accumulated sediments in shallow fish spawning or breeding waters,
which will remove an internal loading source and subsequently improve habitat
and spawning opportunities (Action Item B);
· Stabilize eroded shoreline areas to reduce sediment and nutrient loadings near
the shoreline, which will improve shallow water habitat and spawning areas
(Action Item C); and
· Improve water quality to support a more balanced vegetative community and
increase aquatic macrophyte population, which will improve food sources and
fish habitat (Action Items A - C).
Until the aforementioned lake and watershed alternatives are implemented, the
District 14 IL DNR fisheries biologist recommends no changes to the existing fisheries
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management plan. The current management plan includes sampling and monitoring,
and enforcement of current fishing regulations (Pontnack personal communication,
2006.) The following IL DNR management practices and regulations should be
continued: 1) two poles per angler with line fishing only; 2) channel catfish - six fish
daily creel limit; and 3) spring fish population survey consisting of electrofishing and gill
net sampling (every third year or as State budget funding allows).
In the event that water quality and habitat conditions improve within Lake
Carlinville, several alternatives have been identified to address fish population
imbalances within Lake Carlinville.
1) Periodic or annual lake drawdowns during the winter months to
consolidate forage fish and to promote their predation;
2) Electro-shocking and selectively harvesting/removing undesirable fish
species from the lake;
3) Stocking top predators (hybrid striped bass) to increase predation of
undesirable fish species;
4) Opening the lake to commercial fishing in order to harvest/remove
undesirable fish species from the lake;
5) Remove all existing fishing regulations on the lake to remove undesirable
fish species;
6) Eradication of the entire fish population using a piscicide and “starting
over” through stocking;
7) Installing fish attractors/habitat structures to provide cover, and
concentrate fish to improve angler opportunities; or
8) Nothing – allow lake fish population to continue to develop, as is.
Proposed Actions
Periodic lake draw downs to promote increased fish predation, electro-shocking
and selectively harvesting undesirable fish, and stocking top predators may
have limited success in restructuring the fish population in Lake Carlinville. Many of the
undesirable fish species (i.e., black bullhead catfish, warmouth, yellow bullhead catfish,
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common carp, yellow bass, and green sunfish) are bottom feeders that can approach
sizes where existing stunted predator populations may have difficulty consuming them
or the undesirable fish are predators themselves. Selectively harvesting through
electro-shocking, stocking top predators, and opening up the lake to commercial fishing
will have varying costs to cover the fish disposal and stocking costs and costs to offset
potential losses to commercial fishers, as the cost per pound is often less than the cost
of fishing. Removing the existing fish regulations may allow the public to remove
undesirable species from the lake at no cost; however, this may be a very slow process.
Given the variability of the aforementioned alternatives, the IL DNR fish biologist
for Lake Carlinville feels that the most effective treatment may be eradicating the
existing population with an aquatic pesticide or piscicide (e.g., rotenone) and then re-stocking
the lake with largemouth bass, bluegill, redear sunfish, channel catfish, and if
conditions allow, white crappie. However, there is no guarantee that this effort will
prevent undesirable fish species from becoming established again in the future. As a
public water supply lake, the application of a piscicide to eradicate the existing fish
population could have a negative backlash. To help answer potential questions from
concerned citizens, information may need to be distributed to inform and educate the
public. In the event that the City of Carlinville decides to restructure the Lake Carlinville
fish population through the application of rotenone, the City would need to obtain a
permit from the Illinois EPA for application of an aquatic pesticide or piscicide to Lake
Carlinville. The permit would be issued by the Illinois EPA Public Water Supplies Permit
Section. A licensed piscicide applicator (i.e., IL DNR) would be required to apply the
rotenone.
To ensure that nearly all fish in the lake are eradicated, the IL DNR recommends
a concentration of 9 parts per million (ppm) of rotenone. To achieve this concentration,
an application rate of approximately 3 gallons per acre-foot of lake volume would be
required (Pontnack personal communication, 2007). With an estimated lake volume of
1,378 acre-feet and rotenone costs varying from $55 to $60 per gallon, the chemical
costs for Lake Carlinville could vary from $230,000 to $255,000. To increase the
effectiveness of the rotenone, IL DNR recommends applying the treatment in July or
preferably August, typically when fish eggs are not present. During the rotenone
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application and treatment, the City of Carlinville will have to draw water from Lake
Carlinville II for a period of time until the rotenone degrades and naturally attenuates. IL
DNR estimates that this natural attenuation period could last one to two weeks
depending on the rotenone concentration applied. To reduce unit costs and increase
treatment effectiveness, a slight draw down of the lake prior to treatment is suggested.
This could be detrimental to the public water supply if drought conditions arise during
draw down. Additional costs associated with eradicating the lake fish population include
the handling and subsequent disposal of fish bodies.
After the existing Lake Carlinville fish population has been eradicated, IL DNR
fish biologists would re-stock Lake Carlinville at a nominal cost. IL DNR recommends
the following re-stocking densities for Lake Carlinville (Pontnack personal
communication, 2007):
· Largemouth Bass - 100 1”-2” fish per acre
· Bluegill - 350 1”-2” fish per acre
· Redear Sunfish - 150 1”-2” fish per acre
· Channel Catfish - 100 1”-2” fish per acre
· White Crappie - 100 1”-2” fish per acre (if lake conditions allow)
To further enhance the re-stocked fish population, fish attractor/habitat structures
should be installed within the lake to provide cover and concentrate fish to improve
angler opportunities. Rather than placing evergreen trees, which decompose quickly
and can introduce unwanted nutrients into the lake, other more durable methods are
recommended such as wooden log cribs, concrete block or rock rubble piles, stake
beds, plastic structures, and bundled piping. The estimated costs are anticipated to
vary from $250 to $750 for each structure. It is recommended that structures or
structure groupings be located and installed under the direction of the IL DNR District
Fisheries Biologist. The total cost for the structures is estimated to be as much as
$5,000. Examples of potential fish attractors/habitat structures are shown in Figure 34.
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Figure 34. Fish Attractor/Habitat Structure Alternatives
Each of the alternatives presented to address restructuring fish population
imbalances have merit, but it is important to note that no one alternative will accomplish
all the goals. Final selection may consist of a combination of alternatives, which could
be influenced by the success of actions implemented to improve the lake’s aquatic
habitat. Other items to consider in selecting alternatives to restructure the fish
population may include the availability of local and state resources and public
perception.
Objective #3: Promote Lake and Watershed Restoration
The following actions items were identified to promote collaboration and
cooperation between the City of Carlinville, private landowners, and the lake users prior
to and during implementation of the Lake Carlinville Watershed Plan.
E. Conduct Informational and Educational Programs
F. Identify Watershed Coordinator(s)
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The following proposed actions are intended to inform and educate the public
about watershed and lake issues, to change the practices of current and future
generations, and coordinate future watershed and lake restoration projects. Due to the
wide variety of ways the City of Carlinville could encourage project support and the fact
that an evaluation of alternative actions applies to situations where one action will be
chosen, only proposed actions are discussed in this section.
Proposed Actions
Action Item E. Conduct Informational and Educational Programs
Informational and educational (I/E) programs will increase the public’s awareness
of various lake and watershed issues, educate stakeholders on the process of lake and
watershed restoration, and promote future involvement. I/E programs should be
implemented on various levels throughout the community (i.e., schools, scouts, and
local government) in order to engage people with various ages and interests. Programs
and/or activities that could aid in public outreach are described below. While some of
these activities may take place in the Carlinville area, it is important to also plan
activities that target stakeholders in the upper end of the watershed.
Three potential audiences that could be targeted with public outreach materials
and activities include children and organized youth groups, citizens interested in
preserving water quality or the environment, and stakeholders that have the ability to
implement projects in the watershed. Outreach materials may be obtained through
agencies that promote environmental awareness and stewardship, such as Illinois EPA,
Illinois DNR, NRCS, and Macoupin County SWCD. Alternatively, materials specific to
the Lake Carlinville watershed can be created by a City representative, environmental
consultant, or another designated person (see Action Item F).
Providing teaching materials for science classrooms, conducting field trips to
project sites, developing small projects that can be implemented by scouts or other
youth groups (i.e., planting trees on Arbor Day or Earth Day), and demonstrations at a
lake or watershed festival can be used in combination to target the younger generation.
In order to encourage children to talk with their parents about the environment, flyers
can be sent home from school with children. Contacting a classroom or youth group to
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develop an educational brochure would be one way to distribute information with a
personal touch. The IL EPA sponsored Lake Education Assistance Program (LEAP) is
a great resource to aid in getting children involved with lake and watershed educational
activities.
The general public and watershed stakeholders can be reached by distributing
educational materials or having a festival that would not only raise public awareness of
lake and watershed restoration, but motivate stakeholders to implement projects on
their own land. Interested parties in the general public may include homeowners in the
City’s tax base that use water from Lake Carlinville, and recreational lake users that
would like to see an improvement in lake aesthetics or sport fishing. Hosting a festival
at Lake Carlinville would be a great way to get the general public involved by teaching
all ages about lake impairments and restoration activities and also providing an
opportunity to distribute information about current impairments and upcoming projects.
In order to target stakeholders in the upper end of the watershed, another activity
such as a barbeque or field trip to a demonstration plot could be held to help promote
implementation of lake and watershed best management practices. The City is
encouraged to develop a demonstration plot that can be used as a tool to demonstrate
commitment to lake and watershed restoration and display a variety of BMPs that others
can consider implementing on their own land. Additionally, a demonstration plot on
private property would promote stakeholder participation. Educational materials for
stakeholders should focus on encouraging land practices that will reduce nonpoint
source pollution and funding opportunities specific to managing agricultural and forested
land since these are the major land uses within the Lake Carlinville watershed.
Developing a brochure that summarizes the Lake Carlinville Watershed Plan may be
useful for targeting the general public and watershed stakeholders. An initial sum of
$15,000 is proposed to develop various community I/E programs, including a brochure
that can be mailed to the public and distributed at activities within the watershed.
Action Item F. Identify Lake and Watershed Coordinator(s)
The prioritization, implementation, and completion of the projects listed within the
Lake Carlinville Watershed Plan will require oversight by the City of Carlinville. A lake
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and watershed coordinator is needed to identify additional project locations and manage
projects through their various phases (i.e., planning, permitting, design, and
construction). Therefore, HDR│CWI recommends that the City have a dedicated
person(s) assigned or hired on a part-time basis to oversee lake and watershed
restoration activities. Since stakeholder participation was limited during this study, it will
be critical to have someone local to the area to aid with identifying areas and
cooperating stakeholders for future projects. Several options include 1) the current lake
commission; 2) a City employee or member of the City council; or 3) a
consultant/technical expert (e.g., SWCD employee). Another option would include
engaging the lake commission in planning, decision making and creating awareness,
but also contracting a consultant to help secure funding and implement projects
identified within this report. A range of $10,000 to $20,000 per year may be necessary
for this effort. The responsibilities of this person(s) will include developing and
distributing educational materials and/or programs, aiding in identification of potential
project locations and cooperative landowners, coordinating with landowners that will be
implementing projects, preparing grant applications, and overseeing projects for which
grants are awarded.
D. BENEFITS EXPECTED FROM IMPLEMENTATION OF WATERSHED PLAN
The ecological, social, and economic benefits of watershed management and
lake restoration can extend over many generations. Continuous management of Lake
Carlinville and its watershed can improve various recreational opportunities, increase
community property values and the local tax base, reduce or prevent future increases in
water treatment costs, and provide habitat for game fish and other wildlife. Once
implemented, the proposed actions from the Lake Carlinville Watershed Plan will reduce
sediment and nutrient loadings to the lake and generate a wide range of water quality
improvements, which will produce recreational use benefits and enhance the public
water supply. Specific benefits in relation to completion of each objective in the Lake
Carlinville Watershed Plan are listed in Table 30.
Objectives Action Items Benefits Expected from Lake Carlinville Watershed Plan Objectives
Prevent loss of valuable land and protect agricultural fields
Prolong benefits of sediment removal
Progress toward satisfying TMDL requirements (51% phosphorus load reduction)
Remove Lake Carlinville from the 303(d) list of impaired waters
Prevent further lake degradation, thus increasing property values
Increase lake water depths and navigation of the lake
Reduce internal regeneration of nutrients from bottom sediments
Reduce resuspension of sediments
Improve aquatic macrophyte and fish habitat
Enhance aquatic macrophyte habitat
Reduce (or prevent future increases) water treatment costs
Enhance lake aesthetics & recreational opportunities, including benefits of Objective #2
Decrease frequency of taste and odor problems in public water supply
Increase lake dissolved oxygen concentrations
Reduce blue-green algal dominance and encourage diverse, beneficial algal populations
Accomplish Items A, B, and C; and Decrease presence of undesirable rough fish
Increase sportfish population
D- Restructure Existing Fish Population Increase property values
Draw more visitors to the Lake Carlinville area
Inform stakeholders about technical and financial assistance available
Increase stakeholders' interest in maintaining the environment around them
Provide opportunities for public to learn more about lake and watershed issues
F- Identify Watershed Coordinator Promote collaboration between the City of Carlinville, private landowners and lake users
Increase likelihood that the Lake Carlinville Watershed Plan will be successful
C- Stabilize and Protect Eroded Lake
Shoreline Areas;
B- Remove Accumulated Sediment from
the Lake
Table 30. Potential Benefits Expected from Implementing the Lake Carlinville Watershed Plan
#3 Promote Lake and
Watershed Restoration
#2 Enhance Lake Aesthetics and
Recreational Opportunities
A- Reduce the Amount of Sediment and
Nutrients #1 Improve Water Quality Entering the Lake;
E- Conduct Informational and Educational
Programs
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Overall, the reduction of sediment and nutrients entering the lake and the
removal of nutrient rich lake bottom sediments, together with various habitat
improvements and shoreline stabilization will improve water quality and aid in the
restoration of Lake Carlinville. Improved water quality and clarity will improve the public
water supply and also enhance lake recreation and aesthetics. These improvements
will be reflected by economic benefits such as increased property values, economic
development, and revenues for merchants in the local community.
Table 31 shows the current use estimates for Lake Carlinville, along with the
projected use benefits following implementation of the watershed plan. Prior studies
completed by the IL DNR Planning Division have estimated that a 20 percent increase
in total lake usage can be expected with the implementation of a lake restoration
program that will improve and protect water quality, fisheries, and recreational
opportunities. The economic value was calculated using a multiplier of 1.5 as
suggested by Griffith and Associates (1990). It is estimated that the proposed
restoration program has the potential to generate a total of $1.37 million in economic
benefits over a ten-year period, which does not include the probable increase in
revenues for area merchants as a result of greater lake usage.
A report prepared by JACA Corporation (1980) for the USEPA assessed the
economic benefits derived from 28 projects in the Section 314 - Clean Lakes Program.
The report found that a total return in benefits of $4.15 per total project dollar was
achieved. The projects produced benefits in 12 categories that included recreation,
aesthetics, flood control, economic development, fish and wildlife, agriculture, property
value, public health, public water supply, education, research and development cost,
and pollution reduction. The report also indicated that while many benefits could not be
measured in monetary terms, the success of many Clean Lakes Program projects
appears to have been a catalyst for other community activities.
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Table 31. Projection of Economic Benefits
Total Economic
Change Value of Value of Value of Value of Benefit Using
Recreational Baseline Projected in Baseline Projected Annual Benefit (c) 1.5 Economic
Use Usage (a) Usage (a) Usage (a) Usage (b) Usage (b) Increment (b) (10 Year) Multiplier
Combined
Usage 59,200 71,040 11,840 $458,208 $549,850 $91,642 $916,416 $1,374,624
(a) - in annual user days unless otherwise noted
(b) - in current dollars
(c) - net present value over duration of benefits
Source: NRCS, 1996
Illinois DNR Planning Division
Griffith and Associates
E. BUDGET AND SCHEDULE
The Lake Carlinville Watershed Plan Budget is contained within Table 28.
Recommended actions and management practices within the watershed plan are
divided into two groups. Group #1 includes specific recommended watershed and lake
actions and management practices on City-owned property (i.e., Lake Carlinville and
property surrounding the lake) and other areas located near Lake Carlinville where
HDR|CWI was permitted to access private property. Group #2 consists of actions and
practices that are proposed for the areas of the Lake Carlinville watershed that were not
accessed during field surveys.
Rather than committing to a fixed budget and schedule (i.e., where funding and
restoration projects are specified beforehand), a more open and flexible approach is
proposed. This approach will consist of preparing separate, individual 319-grant
applications (annual August 1 deadline) that are based on the findings and
recommendations of the Lake Carlinville Watershed Plan (Table 28, page 113). This
“phased” approach will allow individual projects to be completed in a reasonable time
frame, as funding becomes available.
Several general criteria are suggested in selecting and prioritizing projects within
the Lake Carlinville Watershed Plan. Priority should be given to projects located on
publicly-owned lands or on lands in which private landowners are cooperative and
willing to implement projects and/or management practices. Generally, projects on
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publicly-owned land have fewer issues with land access and acquisition. Additional
consideration should be given to those projects and management alternatives that will
have the greatest impact on reducing sediment and nutrient (particularly phosphorus)
loadings to the lake (see estimated load reductions in Table 28).
Removing accumulated lake sediments will enhance and increase the longevity
of several other lake projects. HDR|CWI recommends lake sediment removal before
the following activities are considered: sediment and nutrient control basin, lake
aeration, and restructuring the fish population. In order minimize maintenance of
accumulated sediments and materials in the control basin, the City should consider
implementing various BMPs in the lower portion of the watershed, which is in close
proximity to Lake Carlinville. For the other areas within the Lake Carlinville watershed,
projects and practices should be implemented and completed as cooperative private
landowners are identified and project match funds are available. Overall, a ten-year
implementation schedule is estimated for the Lake Carlinville Watershed Plan in Table
32. The recommended actions of the watershed plan are grouped in the
implementation schedule by objective.
Recommended Actions Time-Frame 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
Objective # 1 Action Items
Reduce Sediment and Nutrients Entering the Lake * On-Going X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
City Property & Private Landowners Near Lake Carlinville Short-Term X X X X X X X X X X X X X X X X
Watershed Between Lake Carlinville & West of Route 4 Mid-Term X X X X X X X X X X X X X X X X
Watershed East of Route 4 Long-Term X X X X X X X X X X X X X X X X
Stabilize and Protect Eroded Lake Shoreline Areas Short-Term X X X X X X X X X X X X X X X X X X X X
Survey Streambanks of Honey Creek Mid-Term X X X X X X X X X X X X
Remove Accumulated Sediment - Hydraulic Dredging Mid-Term X X X X X X X X X X X X X X X X X X X X X X X X
Construct Sediment & Nutrient Control Basin Mid-Term X X X X X X X X X X X X X X X X X X X X X X X X
Objective # 2 Action Items
Restructure Lake Carlinville Fish Population Long-Term X X X X X X X X X X X X X X X X X X X X X X X X
Objective # 3 Action Items
Identify Watershed & Lake Coordinator(s) Short-Term X X X X
Conduct Educational & Informational Programs On-Going X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
Continue Water Quality Monitoring On-Going X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
Complete US EPA & IL EPA Grant Applications and Reports On-Going X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
2012 2013 2014
* Conserv. Tillage, Crop Rotation, Conserv. Buffers, Nutrient Management Plans, Inspect/Upgrade Septic System, Changing Landscape Practices, &
Livestock Exclusion from Waterways, Water & Sediment Control Basins, Drainage Water Management, Silviculture Practices, Gully/Grade Stabilization
Structures, Grassed Waterways, Ponds, Restororation of Riparian Corridors, and Stream Bed & Stream Bank Stabilization
Table 32. Recommended Implementation Schedule for Lake Carlinville Watershed Plan
2008 2009 2010 2011 2015 2016 2017
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F. MEASURING PROGRESS AND MONITORING WATER QUALITY
As projects within the watershed plan are implemented, it is important to have
targets and subsequent methods to measure progress. For systems such as Lake
Carlinville where eutrophication and sediment are major problems, the US EPA (2005)
recommends the following indicators to measure progress in reducing pollutants:
Eutrophication:
· Phosphorus loads
· Number of nuisance algal blooms
· Transparency of lake or Secchi transparency depth
· Frequency of taste and odor problems in water supply
· Hypolimnetic dissolved oxygen in lake
Sedimentation:
· Total suspended solid concentrations and loads
· Raw water quality at drinking water intake
· Frequency & degree of dredging of impoundments & water supply intakes
Due to the qualitative nature of the load reduction indicators above, quantitative
measurable milestones were developed to assist with implementation of the Lake
Carlinville Watershed Plan. Together, the indicators and measurable milestones can be
used to monitor progress and determine the effectiveness of the implemented
watershed plan. Measurable milestones, estimated time frames, and estimated load
reductions are listed for each proposed action (Table 33). While larger projects can be
divided into phases, some projects will be completed at one time and do not have
measurable milestones.
It should be noted that the rate in which loads can be reduced and measurable
milestones can be achieved are often dependent on the nature of the pollutants. Unlike
pathogens, which tend to die off quickly once the source is removed, management
practices and erosion controls designed to reduce phosphorus loadings often do not
have immediate observed effects. In cases where phosphorus is the problem,
measurable milestones or changes may take years to demonstrate a response to
watershed management practices.
Recommended Actions
Measurable
Milestones
Estimated Time
Frame
Sediment
(tons/yr)
Nitrogen
(lbs/yr)
Phoshorus
(lbs/yr)
General Load Reduction Indicators
A - Reduce the amount of sediment and nutrients entering the lake
Nutrient Management Plans 250 Acres 3 to 5 years NA 131 12 Reduction in soil erosion within watershed
Crop Rotations 250 Acres 3 to 5 years 564 1,162 581
Conservation Tillage 250 Acres 3 to 5 years 741 1,580 790 Reduced TSS & P loads to Lake Carlinville
Conservation Buffers 50 Acres 3 to 5 years 64 189 101
Septic & Holding Tank Inspections & Upgrades Lake properties 2 to 3 years ** ** **
Changing Landscape Practices Lake properties 3 to 5 years ** ** **
Livestock Exclusion from Waterways 2 locations 3 to 5 years 10 248 80
Gully/Grade Stabilization Structures 1,000 linear feet 3 to 5 years 159 319 159 Improved public water supply
Ponds 2 Ponds 3 to 5 years 106 19 10
Grassed Waterways 25 Acres 3 to 5 years 525 1,075 525 Increased Secchi transparency depths
Restoration of Riparian Corridors 25 Acres 3 to 5 years 193 153 77
Silviculture Practices 25 Acres 3 to 5 years 193 153 77 Increased in hypolimnetic DO
Drainage Water Management 100 Acres 3 to 5 years 92.0 2,475.0 180.0
Stream Bed & Bank Stabilization 500 linear feet 3 to 5 years 114 227 114 Increased Secchi transparency depths
Water & Sediment Control Basins 10 Structures 3 to 5 years 424 96 48
Sediment & Nutrient Control Basin Constructed Basin 5 to 8 years * 12,306 17,200 5,200 Reduced number of algal blooms in lake
B - Remove Accumulated Sediment from the Lake Improved aquatic and fish habitat
Lake Sediment Removal 500,000 cu. yds. 4 to 7 years 33,422 1,091,610 109,161
C - Stabilize and Protect Eroded Shoreline Areas
Lake Shoreline Stabilization 2,200 linear feet 3 to 5 years 263 525 263
* To be completed after sediment removal.
** Load reductions vary. Additional load reduction information is included in Appendix F.
Estimated Load Reductions
Reduction in freq. taste & odor problems in
public water supply
Table 33. Measurable Milestones for Lake Carlinville Watershed Plan
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As recommended actions and alternatives within the Lake Carlinville Watershed
Plan are implemented and completed, additional monitoring and reporting is
recommended to document and demonstrate progress (i.e., meeting the proposed
TMDL reductions). Several of the federal and state EPA grant programs have
monitoring and project reporting requirements to assess and document the
effectiveness of implemented projects and management practices. Monitoring will also
help track watershed plan progress so that adjustments can be made, if necessary. A
range of $13,000 to $20,000 for sample analyses and $40,000 to $60,000 for additional
project reporting is recommended for budgeting purposes.
The Illinois EPA conducts two lake monitoring programs and three stream
monitoring programs. The Ambient Lake Monitoring Program (ALMP) samples
approximately 50 lakes annually, the Volunteer Lake Monitoring Program (VLMP)
encompasses sampling at more than 170 lakes per year, the 213-station Ambient Water
Quality Monitoring Network samples rivers and streams statewide, the Intensive Basin
Survey Program surveys major watersheds on a five-year basis, and the Facility-
Related Stream Survey Program conducts approximately 20-30 stream assessments
each year. The Illinois EPA’s ALMP considers Lake Carlinville as a core lake and thus
the lake is sampled every four years (Borland Lau personal communication, 2006).
Lake Carlinville is strongly encouraged to participate in the VLMP to help monitor and
document changes in lake water quality. Any of the existing Illinois EPA sampling
programs could be used to monitor the progress of the Lake Carlinville Watershed Plan.
The City of Carlinville is also encouraged to conduct additional monitoring to
assess sources of pollutants and evaluate changes in water quality. Table 34 presents
a proposed water quality monitoring program for a one-year period following
implementation of the proposed lake and watershed restoration activities. This program
is similar to the Phase 1 water quality monitoring program; however, no organics,
metals, sediment or fish samples will be analyzed.
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Table 34. Water Quality Monitoring Program
Parameter Sampling Frequency
Total Phosphorus M,S,T
Dissolved Phosphorus M,S
Ammonia-Nitrogen M,S,T
NO2 +NO3 -Nitrogen M,S,T
Kjeldahl-Nitrogen M,S,T
Total Suspended Solids M,S,T
Volatile Suspended Solids M,S
Turbidity M,S
pH M,S
Alkalinity M,S
Conductivity M,S
Chlorophyll a, b, c M,S
Phytoplankton M,S
Transparency - Secchi Disc M,S
Diss. Oxygen/Temperature Profile M,S
Key: M = monthly in-lake and tributary sampling (12 times per year by the City of Carlinville)
S = summer in-lake and tributary sampling (Apr., June, July, Aug., & Oct. by Illinois EPA)
T = Storm event tributary sampling (by the City of Carlinville/HDR│CWI, as required)
All parameters except chlorophyll (a, b, c), phytoplankton, Secchi transparency and dissolved
oxygen/temperature profiles will be taken one foot below the surface at Sites 1, 2, and 3, and one foot
above the botto