7.0
Lake and Watershed Management Plan
7.1
Goals
In this report Lake Carey has been studied as two separate, but linked water bodies. There is the
larger, deeper, upper section referred to as the “lake”, and there is the smaller, shallower, lower
section referred to as the “pond.” Both are highly eutrophic; the pond can be classified as hyper
eutrophic.
The goals of this management plan are to protect Lake Carey from further degradation, and to
reduce the present eutrophic condition of Lake Carey to a mesotrophic condition, or, at the very
least, a less eutrophic condition. These goals are quantified in Table 7.1
Lake Classification
Total Phosphorus
Chlorophyll a
Blue-Green Algae
Table 7.1
Quantitative Water Quality Goals for Lake Carey
Present Condition
Goal
Eutrophic – Hypereutrophic
Border line Eutrophic
0.044 mg/l – 0.072 mg/l
0.025 – 0.030 mg/l
6 – 43 ug/l
6 – 10 ug/l
High, Dominant
Low, Non-Dominant
These goals can be realized by reducing the amount of nutrients (nitrogen and phosphorus) and
sediments entering Lake Carey. Specifically, these goals can be achieved by implementing a
program that consists of erosion and stormwater control, wastewater management, public
education, and the adoption of ordinances to properly manage any future growth. Except for
specific in-lake restoration measures, such as dredging or nutrient inactivation which are specific
for the “lake” or “pond”, the recommended management plan applies to all of Lake Carey, both
the “lake” and the “pond.”
7.2
Overview of Management Plan
An effective management plan must include both in-lake management practices and watershed
management practices. Due to the high amount of nutrients entering and present in Lake Carey,
however, the emphasis of the management plan should initially be placed on watershed
management, on reducing the nutrients and sediments entering Lake Carey. After the nutrient
and sediment loads to the lake are reduced, the emphasis of the management plan may shift to inlake management measures. Dredging of the “pond”, however, should be investigated during the
initial stages of the management plan since dredging of the unconsolidated sediments would
remove a significant amount of nutrients, resulting in a lowering of the internal phosphorus
loading.
The lake and watershed management plan consists of the following elements:
1.
2.
3.
4.
5.
Watershed Management
Wastewater Management
In-Lake Management
Public Education
Water Quality Monitoring
Each of these management plan elements are discussed in the following sections.
7.3
Watershed Management
Managing the Lake Carey watershed is the key to reducing the excessive sediments entering
Lake Carey. It is also important for reducing the nutrient loading to Lake Carey. As discussed in
Section 4.0, Lake Carey has very high concentrations of phosphorus and nitrogen; it also has
large volumes of unconsolidated sediments (1.2 million cubic yards in the lake and 291,200
cubic yards in the pond). In-lake treatment measures such as phosphorus inactivation and
aeration will not be effective until the nutrient and sediment loadings to Lake Carey are
significantly reduced.
The watershed management program should consist of the following:
1.
Control of Existing Erosion and Stormwater Runoff,
2.
Control of New Development and Related Erosion and Stormwater
Runoff, and
3.
Control of Erosion and Stormwater Runoff from Agricultural Activities
Each of these management plan elements are discussed in the following sections:
7.3.1
Control of Existing Erosion and Stormwater Runoff
The main source of the siltation of Lake Carey is soil erosion and stormwater runoff. Much of
the siltation of the lake appears to have been caused by erosion and stormwater runoff during and
after construction from existing residential and commercial buildings, roads, parking lots,
driveways, unvegetated areas, and tree removal. Control of soil erosion and stormwater runoff
from existing areas of the watershed can be accomplished by retrofitting existing problem areas,
implementing homeowner practices, installing shoreline and streambank vegetated buffers, and
mitigating erosion and stormwater runoff from existing dirt and gravel roads.
Retrofitting Existing Problem Areas
Section 5.0 – Watershed Evaluations identified a variety of erosion and stormwater runoff
problems throughout the Lake Carey Watershed. The watershed problem areas identified in
Section 5.0 should be corrected. These problem areas consist of roads, culverts, gullies, drainage
ditches, driveways, and unvegetated lakeshore areas that contribute eroded soil and polluted
stormwater to Lake Carey.
The best method to control erosion and polluted stormwater runoff from these areas is specific to
each site. In general, however, the basic stormwater management practices that are applicable to
the Lake Carey watershed consist of the following:
1.
Maximize the use of natural bioengineering methods that use vegetation
and retention to slow down the stormwater runoff, retain the runoff,
reduce soil erosion, and filter pollutants from the runoff,
2.
Minimize the use of impervious surfaces and storm sewers to transport
untreated, polluted runoff to Lake Carey,
3.
Where storm sewers are used, direct the stormwater over vegetated areas,
not directly to streams or Lake Carey, and
4.
Vegetate areas along roadways and commercial establishments to reduce
soil erosion.
This report identifies many nonpoint source problem areas. Most of these are public areas around
the watershed. There are, however, many private areas that have significant erosion and
stormwater runoff problems. Many of the homes in the watershed are located on small, steepsloped, highly impervious lots. An important element of the management plan, therefore, should
be to inform homeowners and commercial establishments about erosion and stormwater
problems and provide information that will help them correct and retrofit problem areas on their
home and commercial sites.
Homeowner/Commercial Site Practices
Homeowners and owners of commercial establishments should be encouraged to implement
environmentally-friendly practices on their sites. The following practices should be encouraged:
1.
Keep site disturbance to a minimum, especially avoid the removal of
natural vegetation and the exposure of bare soil,
2.
Seed and mulch any bare soil in the yard and especially near shoreline
areas to prevent loss of soil during rain storms,
3.
Leave naturally vegetated areas along the lake shore, streams, and road
ditches,
4.
Plant deep rooted woody, native vegetation along lake shores, streambeds
and road ditches,
5.
Minimize the use of herbicides, pesticides and fertilizers on yards and
gardens,
6.
Stabilize steep slopes with ground cover, mulches or stone,
7.
Create a “buffer zone” of natural vegetation between buildings and the
water. Trees, grasses, and shrubs will stabilize shorelines. If ground has
been disturbed, place an erosion barrier such as straw bales at the bottom
of the slopes. This will retain sediments while ground cover is being reestablished, and
8.
Do not cut down trees unless absolutely necessary. Trees provide many
environmental benefits including soil stabilization, nutrient uptake, and
evapotranspiration of stormwater.
Most homeowners and owners of commercial establishments do not realize that they should be
implementing these practices. Implementation of these practices can best be accomplished by
including a description of these practices in fact sheets, newsletters and websites as part of the
public education program recommended in Section 7.7.
Shoreline and Streambank Vegetative Buffers
Shoreline landscaping affects the condition of Lake Carey. The most common shoreline
landscape around Lake Carey is a lawn planted with grass leading to the shoreline or a bulkhead.
There are several problems with this type of landscaping. Grass lawns do not effectively filter
nutrients, such as phosphorus, from stormwater runoff. In fact, the use of fertilizers on grass
lawns increases the amount of nutrients entering Lake Carey. Vegetated buffers of native plant
species should be encouraged for the shoreline of Lake Carey and for the tributary streams of
Lake Carey.
Vegetative buffers have the following advantages:
1.
Emergent vegetation in the lakes, like bulrushes and cattails, reduce
shoreline erosion caused by wind and boat traffic,
2.
Natural vegetation along the shoreline serves as a filter that helps prevent
sediment, nutrients, fertilizers and pesticides from entering the lake,
3.
Vegetative buffers reduce the amount of fertilizers and herbicides needed
on a shoreline property because the resulting lawn is smaller, and native
plants in the buffer zone do not need fertilizers or herbicides, and
4.
Unmowed wildflowers, grasses, and sedges along the shore create a
biological barrier that will deter Canada geese.
Streambank Stabilization
Erosion is one of the major sources of nonpoint source pollution in watersheds. Certain
nutrients as well as many other “pollutants” adhere to eroded soil particles and are
transported to the streams and to Lake Carey. Several streams flowing into Lake Carey
have eroded streambanks and lack adequate vegetation. It is likely that other areas of
streambank erosion exist along the tributaries on private land that could not be inspected
as part of this project.
Restoration of eroded streambanks is a cost-effective way to significantly reduce
sediment and nutrient loadings to Lake Carey. By using bioengineering (vegetative) or a
combination of bioengineering and structural engineering streambank stabilization
techniques, the erosion problem can be corrected while the stabilized streambank can
serve as a vegetative buffer and, in many cases, a restored riparian corridor. Riparian
buffers along the streams will reduce the quantities of sediments and nutrients that enter
the streams via stormwater runoff.
A variety of methods are designed to stabilize eroded streambanks and reduce continued
erosion and sedimentation. Some methods reduce the amount and velocity of water in the
stream, others involve relatively high cost structural controls such as rip-rap and gabions,
and still others involve relatively low-cost controls such as willow twigs, grasses, shrubs,
or wetland vegetation. Lower cost, bioengineering approaches should be used wherever
practical to stabilize the severely eroded streambank areas noted on the nonpoint source
problem area map. Where warranted, a structural stabilization element should be included
in the overall project design to ensure long term stabilization and to provide adequate
protection against high streamflows and high flow velocities.
Gravel Roads
There are three gravel roads on private property in the Lake Carey watershed that are located on
very steep slopes. These roads contribute sediment and nutrients to Lake Carey due to transport
of polluted stormwater to Lake Carey and the erosion of the roads.
The solution for each road is similar. As shown in Figures 7.1 to 7.3, Roads 1 through 3 all need
the same basic solution:
1.
The roads should be paved to eliminate soil and gravel erosion from each
road.
2.
When the roads are paved, they should be sloped so that stormwater runoff
drains to the sides of the roads and into vegetated areas where the
stormwater will be slowed down, filtered, and infiltrated.
3.
Bioretention-Swale Treatment Systems should be constructed on the lake
side of each road as shown on Figures 7.1 to 7.3. A schematic of the
Bioretention-Swale is shown in Figure 7.4. Stormwater from the paved
roads will flow over the road and into the Bioretention-Swale System. The
rock-lined forebay will remove the larger particulate matter before
stormwater flows into the vegetated bioretention system where stormwater
will be stored, filtered, and infiltrated. Treated stormwater will discharge
from the Bioretention System into a grass swale which will further filter
the stormwater before it reaches the lake.
Road 1 has an existing storm culvert under the road. Stormwater runoff from the culvert should
be directed to the Bioretention-Swale Treatment System.
7.3.2
Control of New Development and Related Erosion and Stormwater Runoff
Much of the present siltation of Lake Carey occurred years ago when houses, roads, and other
infrastructure were constructed prior to the restrictive erosion and sedimentation regulations and
controls presently being enforced. If properly designed and inspected, present day erosion and
sediment control plans should protect Lake Carey from excessive siltation. The best strategy, of
course, is prevention; new construction within the lake’s watershed should be minimized.
When new development is proposed, controlling soil erosion and stormwater runoff during
construction and after construction is critical. If not properly controlled, they will be a significant
source of additional nutrients and sediment to Lake Carey. In fact, uncontrolled construction
activities produce one of the highest pollutant loads to any waterbody. Construction of
individual homes does not always require an erosion and sedimentation plan and its review. The
township ordinances should be amended to require the development and review of such plans for
all earthmoving and building activities.
The long-term erosion and stormwater runoff caused by new development is a matter of even
greater concern. Unlike erosion from construction activities which only lasts during the
construction period, erosion and stormwater runoff from post-construction development lasts
forever. New development produces more impervious areas such as buildings, driveways,
parking lots, and roads. Impervious surfaces cover soils that once infiltrated stormwater into the
groundwater. Impervious surfaces, therefore, cause nonpoint source pollution in a variety of
ways:
1.
Impervious areas significantly increase the peak rate, velocity and volume
of stormwater runoff.
2.
Runoff from impervious areas washes pollutants such as nutrients,
sediments, and bacteria into streams and lakes.
3.
Runoffs from impervious areas have a higher temperature than pervious
areas. The higher temperature can adversely affect the plant and animal
life in streams and lakes, and
4.
The larger volume and higher velocity of stormwater runoff from
impervious surfaces causes soil erosion, shoreline erosion, and streambank
erosion.
To address these serious threats to the future of Lake Carey, the landowners within the lake’s
watershed should be encouraged to grant conservation easements, especially on properties with
sensitive areas such as wetlands, streams, and lake shorelines. To minimize the adverse impacts
of stormwater runoff from any new development, the townships should adopt the following new
ordinances: riparian buffer, conservation and stormwater management. In addition, the existing
Zoning Ordinance should be revised.
Conservation Easements
Conservation Easements help preserve open space, protect critical areas from development, and
concentrate development in areas that are already disturbed. A conservation easement is a
voluntary agreement that allows a landowner to limit the type or amount of development on their
property while retaining private ownership of the land. The easement is signed by the landowner,
who is the easement donor, and a land trust or conservancy, who is the party receiving the
easement. The easement applies to all future owners of the land. By granting a conservation
easement a landowner can assure that the property will be protected from unwanted development
forever, while maintaining ownership of the land. An additional benefit of granting a
conservation easement is that the donation of an easement may provide significant financial
advantage to the donor.
Residents of the Lake Carey watershed who own land within the watershed, especially in critical
areas such as lake shorelines, wetlands, and riparian areas around streams, should be encouraged
to develop conservation easements to protect the property against future development. The
development pressure is extremely high in the watershed, but if protective measures are in place,
the sensitive areas can be protected. The Lake Carey Cottages Association should continue to
work with the Countryside Conservancy and North Branch Land Trust to offer workshops for
watershed residents on conservation easements.
Riparian Buffer Ordinance
A riparian buffer ordinance should be adopted to require buffers along wetlands, streams, and
lake and pond shorelines for all new construction projects. A buffer of approximately 75 feet
should be sufficient to protect water quality along wetlands and streams. A 50-foot buffer is
more realistic for lake and pond shorelines. The purpose of the riparian buffer would be to (1)
eliminate major earthmoving activities close to the stream, and (2) to filter and infiltrate
stormwater runoff before it reaches the water.
Conservation Ordinance
A conservation ordinance should be adopted to require developers to identify all environmentally
sensitive areas on a site including wetlands, trees, waterbodies, slopes, and soils. An alternative
to adopting a separate ordinance would be to include these provisions in the stormwater
management ordinance.
Stormwater Management Ordinance
A stormwater management ordinance should be adopted by both townships to control nonpoint
source pollution from future development. The stormwater management ordinance should
incorporate the Part II NPDES requirements that the 2-year storm be managed for runoff volume
and water quality. The stormwater ordinance should refer to the new Pennsylvania DEP Best
Management Practices (BMP) Manual and require its use in all new development. The
stormwater ordinance in conjunction with the DEP BMP Manual should require that low impact
development concepts be incorporated into all new development plans. Low impact development
is an innovative, ecosystem-based approach to land development and stormwater management.
The general goals of low impact development are to reduce the amount of impervious area on a
site and to infiltrate and treat stormwater runoff. Low impact development mimics the predevelopment hydrology and controls the peak flow, volume, and quality of stormwater runoff. It
does this by minimizing the effective impervious area (the impervious area that produces
stormwater runoff) and directing stormwater runoff onto vegetated areas that treat, infiltrate, and
evaporate the runoff.
The primary planning concepts of low impact development include the following:
1.
Maintain-improve the site hydrology,
2.
Control stormwater at the source,
3.
Use a variety of small BMPs rather than one or more large detention
basins,
4.
Maximize the use of natural, non-structural control methods,
5.
Minimize the use of storm sewers, and
6.
Create a multifunctional environment that includes stormwater control and
treatment, habitat for wildlife, and aesthetics.
Case studies of low impact development around the country have shown that these developments
reduce stormwater volume, protect water quality, provide greener developments, and are costeffective.
Zoning Ordinance
The existing zoning ordinance should be revised to incorporate the significant elements of the
stormwater management ordinance and low impact development concepts. Specific areas of the
zoning ordinance that may need revision include:
1.
Housing density,
2.
Setbacks and yard lines,
3.
Road widths,
4.
Cul-de-sac lengths,
5.
Curb and gutter, and
6.
Stormwater detention requirements.
It is important that all of the municipal ordinances work together and do not conflict with each
other.
7.3.3
Control of Erosion and Stormwater Runoff from Agriculture
There are approximately 1793 acres of agricultural land in the Lake Carey watershed. This
accounts for about 43 percent of the watershed. Agricultural land contributes approximately 38
percent of the annual phosphorus load to Lake Carey.
According to the “Total Maximum Daily Loads (TMDLs) – Lake Carey, Wyoming County”
report developed by the Susquehanna River Basin Commission (2001), agricultural runoff in the
watershed has been largely reduced through best management practices promoted by the
Wyoming County Conservation District. The report indicates that the agricultural management
practices have been recently implemented, but that no monitoring was performed to assess the
effectiveness of the control measures. The Lake Carey Cottages Association should meet with
the National Resource Conservation Service (NRCS) periodically to discuss the progress of
implementing agricultural BMPs and whether or not the BMPs are operating properly.
The NRCS and the Wyoming County Conservation District should continue to work with the
farmers to ensure that agricultural best management practices are applied to all the agricultural
land in the watershed. They should work with the farmers to ensure that all active farms have an
up-to-date conservation plan and nutrient management plan that is being implemented.
7.4
Wastewater Management
It is estimated that the phosphorus loading from septic systems and internal loading is 2196
pounds per year. This accounts for 46 percent of the annual loading. Although it is not possible
to calculate a specific, separate loading for septic systems, it is probable that a significant amount
of the 2196 lbs/year is being contributed by failing septic systems.
As shown in Figure 7.5, a septic system needs several feet of dry soil to properly renovate or
treat the septic tank effluent. If the seasonably high groundwater is at or above the level of the
septic system drainfield, the septic tank effluent will not receive proper treatment and it will
flow, untreated, into the groundwater and ultimately into Lake Carey. Figure 7.6 depicts the soils
in the Lake Carey watershed that are suitable for conventional septic systems. As shown in
Figure 7.6, all of the soils in the watershed have severe restrictions for conventional septic
systems. This indicates that there is a high probability that all of the conventional septic systems
in the Lake Carey watershed are failing and are polluting the groundwater and Lake Carey. Due
to the high contribution of both phosphorus and nitrogen by septic systems, a wastewater
management program should be implemented in the Lake Carey watershed, and this program
should be a high priority.
Figure 7.5 Conventional Septic System
There are several wastewater management options that should be considered:
1.
On-Site Wastewater System Solutions,
2.
Decentralized Wastewater System Solutions
3.
Centralized Wastewater System Solutions
Each of these management options are discussed in the following sections.
Figure 7.6 Suitability of Soils in the Lake Carey Watershed for Septic Systems
7.4.1
On-Site Wastewater System Solutions
On-site solutions to failing septic systems usually include one or more of the following:
1.
Implement a Septic System Management Program that requires regular
pumping of the septic tank,
2.
Repair failing septic systems, and
3.
Replace failing septic systems.
Septic System Management Program
Regular pumping of the sludge in the septic system only works if the septic system is
properly located, designed, and constructed. According to Figure 7.6, none of the soils in
the watershed is suitable for a conventional septic system. Most of the septic systems in
the watershed are conventional systems or sub par systems that do not meet present
standards. These include 55 gallon drums, cesspools and undersized systems.
The septic systems in the Lake Carey Watershed are failing because they never should
have been constructed. The high seasonal groundwater in much of the area precludes the
proper operation of the septic systems. Conventional septic systems would not be
approved under present DEP regulations in most of the watershed. Therefore, a septic
system management program is not a viable solution for most of the existing
conventional septic systems.
Repair Failing Septic Systems
The septic systems are not broken; therefore, they cannot be repaired. As discussed
above, the soils in the Lake Carey Watershed are not suitable for conventional septic
systems. Therefore, repair of failing septic systems is not a viable solution.
Replace Failing Septic Systems
Figure 7.7 shows soils in the watershed that may be suitable for other types of on-side
methods, such as drip irrigation, mound systems, and spray irrigation. It may be possible,
therefore, in some cases to abandon the failing septic system and replace it with a nonconventional system. Soil testing consisting of a pit test and hydroconductivity test would
have to be performed on each site to determine whether the site would be suitable for a
non-conventional system.
Figure 7.7 Suitability of Soil for Drip, Spray & Mound Treatment Systems Based
On Groundwater Level and Slope
Replacement of a failing septic system with a non-conventional system has several problems and
limitations:
1.
Availability of suitable soil,
2.
Availability of space on the site,
3.
Proximity to water supply,
4.
Expense of replacement system,
5.
Maintenance of replacement system, and
6.
Lack of statutory authority.
Many of the lots in the watershed are small; therefore, it is highly improbable that sufficient land
with a suitable soil at a proper distance from a water supply well will be available for most
homes. Some of these non-conventional systems are expensive to design and build. Some of
them, especially spray irrigation, requires a significant amount of regular maintenance. A major
drawback to replacement of failing septic systems is the lack of statutory authority by the
townships and others to require that a septic system be replaced. A municipality or other agency
would have to have clear proof that a specific system was failing and polluting a stream, lake or
water supply.
Replacement of failing septic system, therefore, is not a long-term, watershed-wide feasible
solution to failing septic systems.
7.4.2
Decentralized Wastewater
A decentralized wastewater system, also known as a community cluster system, is defined by
EPA as “An onsite or cluster wastewater system that is used to treat and dispose of relatively
small volumes of wastewater, generally from individual or groups of dwellings and businesses.”
A comparison of a centralized vs. decentralized system is presented in Figure 7.8. The
centralized wastewater system uses gravity or pressure sewers to transport all of the wastewater
in the area to one location for treatment and disposal, usually to a stream.
The decentralized wastewater system consists of a variety of clusters where wastewater from
each cluster is transported to a smaller wastewater system for treatment and disposal. A
decentralized wastewater system separates the service area into clusters, and the wastewater from
each cluster is transported to and treated at a separate treatment facility. Instead of one
centralized treatment facility, there are two or more smaller, decentralized wastewater treatment
facilities. The cluster treatment system, being smaller due to the reduced cluster wastewater flow,
may be an on-site system such as a mound, drip system, or spray irrigation system. It could also
be a small package treatment plant that discharges to a stream.
There are several advantages to a decentralized wastewater system:
1.
Decentralized systems can be used to control growth,
2.
Decentralized systems usually do not promote uncontrolled growth like
centralized systems often do,
3.
Decentralized systems often are less expensive to construct and operate.
They often reduce the length of sewers needed and do not sewer
unpopulated areas,
4.
Decentralized systems, consisting of a series of smaller wastewater flows,
have a greater potential for on-site disposal. Most centralized wastewater
systems require a wastewater treatment plant with stream discharge
because of the larger wastewater flows being treated, and
5.
If on-site treatment and disposal is feasible, centralized systems, by using
on-site soil disposal, provides better treatment, better meets EPA and DEP
water quality antidegradation requirements, and recharges groundwater.
There are, however, several disadvantages to decentralized wastewater systems. They usually
require more up-front soils testing to locate suitable sites. They may also require slightly higher
engineering design fees. Although system maintenance would probably be lower than a
centralized system, it could be more complicated due to the multiple cluster systems.
In their report entitled “Response to Congress on Use of Decentralized Wastewater Treatment
Systems”, EPA indicated concern about the gap between wastewater needs and available federalstate funding. The report indicated there is a need to identify and implement alternatives to costly
centralized treatment and collection systems. The conclusion of the EPA report is that
“adequately managed decentralized wastewater systems are a cost-effective and long-term option
for meeting public health and water quality goals.”
Community wastewater systems can consist of gravity sewers, high pressure sewers, or low
pressure sewers. They can use grinder pumps or pump stations to transport wastewater to the
treatment facilities.
Grinder pumps are used to pump raw wastewater into a gravity sewer or pressure sewer. A pump
station usually receives wastewater from gravity sewers and pumps the raw wastewater to the
treatment facility through pressure sewers. An innovative alternative to grinder pumps and pump
stations is the STEP system (Septic Tank Effluent Pump). In a STEP system, as shown in Figure
7.5, a small tank with a sump pump is attached to the outlet of the existing septic tank (the septic
tank is disconnected from the existing drainfield). Septic tank effluent flows in the attached tank
where the sump pump pumps it to a small diameter presser sewer. The pressure sewer transports
the partially treated wastewater to the treatment facility.
The STEP system has the following characteristics:
1.
The existing septic tank is used to settle the raw wastewater.
2.
Only the effluent from the septic tank is treated at the treatment facility.
3.
Sludge must be removed from the septic tank every 2 to 3 years.
STEP systems usually have construction costs that are significantly lower than conventional
systems since they are inexpensive sump pumps and small diameter pressure sewers.
The treatment/disposal system can be soil-based such as a mound, drip system, or spray
irrigation. It also could be a small package treatment plant with a discharge to a stream. It could
be a combination of the above.
Decentralized wastewater systems should be investigated as part of a joint township Act 537
Wastewater Management Plan revision.
7.4.3
Centralized Wastewater System
A centralized wastewater system consists of a centralized wastewater collection system that
transports all of the wastewater from an area to a central wastewater treatment facility. Due to
the normally high wastewater flows from a centralized sewer system, the treatment facility is
usually a wastewater treatment plant with stream discharge.
Like a decentralized system, a centralized system can consist of gravity, high pressure and low
pressure sewers. It could consist of grinder pumps, STEP systems, or pump stations.
Due to the larger size of a central wastewater treatment facility, more treatment system options
would be available. Besides the conventional extended aeration treatment plant, other treatment
options would include the sequential batch reactor (SBR), the oxidation ditch process, and the
phased isolation ditch, an innovative combination of the SBR and oxidation ditch.
There are several concerns associated with a centralized wastewater system:
1.
The system construction costs could be higher than a community
decentralized system primarily due to the larger collection system,
2.
Finding a site suitable for spray irrigation or other form of soil disposal
may not be possible given the poor soil conditions in the watershed,
3.
Due to the latest DEP antidegradation policies and regulations, a stream
discharge may not be economically feasible. The new antidegradation
policies require that all sites capable of on-site disposal must use on-site
disposal, even if a sanitary sewer runs adjacent to the property,
4.
A centralized wastewater system would probably promote growth around
Lake Carey and in other areas of the watershed. Revisions to the zoning
ordinance may provide better growth management in some areas,
however, in developed areas around the lake there are many approved lots
that would be grandfathered into previous zoning regulations, and
5.
A centralized system with stream discharge will reduce the existing
groundwater recharge and lead to a lowering of the groundwater table.
7.4.4
Act 537 Plan Revision
The present Act 537 Wastewater Management Plan should be revised to incorporate the
evaluation of the following alternatives:
1.
Community Decentralized Systems,
2.
Centralized Systems, and
3.
Combination Systems
The Act 537 Wastewater Management Plan should look at all the options discussed above:
cluster systems, different types of sewers, STEP systems, on-site disposal, (mound systems, drip
irrigation systems, spray irrigation systems, etc.), centralized systems, and alternative treatment
facilities.
The Wastewater Management Plan should evaluate all aspects of the various systems including
capital and operating costs, permitting requirements, impacts on streams and Lake Carey, and
impacts on groundwater quality and level.
7.5
In-Lake Management
In-lake management practices that should be considered include:
1.
Lake Dredging
2.
Lake Aeration
3.
Phosphorus Inactivation
These in-lake management practices are discussed in greater detail in the following sections.
7.5.1
Lake Dredging
Lake
The “lake” section of Lake Carey has a mean depth of 18.4 feet and a mean sediment depth of
4.1 feet. Although the lake has a significant accumulation of unconsolidated sediments (1.2
million cubic yards), dredging of the lake is not recommended because (1) there is sufficient
water depth in the lake, and (2) dredging of 1.2 million cubic yards of sediment would be cost
prohibitive. The cost for dredging all of the unconsolidated sediments in the lake would range
from $10,000,000 to $30,000,000.
There are some shallow areas along some of the shoreline. These areas should be spot dredged if
they are a major problem for boating or other recreational activities. Spot dredging of select
shallow areas of the lake, however, will have very little effect on improving water quality in the
lake.
Pond
The “pond” section of Lake Carey has a mean depth of 3 feet and a mean sediment depth of 2.6
feet. Dredging of the pond would have several benefits. It would increase the water depth and
capacity of the pond; it would remove a significant amount of nutrients; and, by removing the
nutrients in the sediment, it would significantly reduce the internal loading of phosphorus to the
pond.
Based on historical dredging costs, costs for dredging of the 291,200 cubic yards of
unconsolidated sediments would range from $2,500,000 to $9,000,000. These costs are based on
projects that required formal public bidding. The dredging costs could be significantly lower if
the lake was drawn down and a local contractor was used to excavate the sediments. Dredging
costs vary based on a variety of factors, including:
1. The volume of unconsolidated sediment. The unit cost per cubic yard
decreases as the sediment volume increased.
2. The chemical composition of the sediment. If the sediment contains toxic or
hazardous chemicals in high concentrations, special disposal sites would be
required, significantly increasing the cost of dredging.
3. The location of the sediment disposal site. Dredging costs increase as the
distance to the sediment disposal site increases.
4. The physical characteristics of the sediment. If the sediment has
characteristics of top soil, some contractors may dredge the lake for a
significantly reduced price because he could use the sediment on construction
projects. In one dredging project where the contractor wanted the sediment,
the dredging cost was reduced to $2 per cubic yard. If the sediment is very
mucky and consists of a lot of organic matter, contractors will usually not be
interested in this kind of sediment, although it has a high nutrient content.
Dredging of the pond should be further investigated via a Dredging Feasibility Study. The study
should include an evaluation of dredging methods, sediment disposal locations, permitting
requirements and project costs.
7.5.2
Lake Aeration
Lake
Dissolved oxygen depletion is a major problem in the lake. During the summer months low or
depleted dissolved oxygen concentrations were observed. For example, in July 2004 the
dissolved oxygen was totally depleted from a depth of 5 meters to the bottom. In August 2003
the dissolved oxygen was depleted from a depth of 4 meters to the bottom.
Dissolved oxygen depletion adversely affects the lake by (1) significantly reducing the habitat
for fish, most of which need about 5 mg/l of dissolved oxygen to survive, (2) eliminating the
benthic macroinvertebrates (bottom aquatic insects), which are food for many fish, and (3)
releasing dissolved orthophosphorus from the sediments under anoxic conditions.
There are two types of lake aeration: total lake aeration and hypolimnetic aeration. Total lake
aeration consists of installing aerator tubing in the bottom of the lake. Air is pumped through the
tubing and enters the lake via small holes in the tubing. This type of aeration breaks up the
thermocline and allows the nutrient-laden bottom waters mix with the top waters of the lake.
Mixing of the nutrient-rich bottom waters with the surface waters would increase the
eutrophication of the lake. Total lake aeration, therefore, is not recommended.
The second type of lake aeration is hypolimnetic aeration. Hypolimnetic aeration consists of
adding air or oxygen to only the hypolimnion (bottom water below the thermocline) of the lake.
The purpose is to aerate only the bottom water where dissolved oxygen depletion occurs.
Hypolimnetic aeration, unlike total lake aeration, does not destratify the lake.
Hypolimnetic aeration should be investigated after a wastewater management system is installed
and the lake does not respond sufficiently to the removal of nutrients from septic systems.
Nutrients from septic systems and residential erosion should be controlled first. Lake monitoring
should be performed to evaluate the improvement in water quality. If more input is required,
hypolimnetic aeration should be further investigated.
Pond
Dissolved oxygen depletion does not occur in the pond due to the shallow condition. Aeration of
the pond is therefore not recommended.
7.5.3
Phosphorus Inactivation
Phosphorus inactivation is a lake restoration process that inactivates phosphorus so that it is not
available for biological uptake by the phytoplankton. There are two general types of phosphorus
inactivation: batch alum treatment and continuous alum treatment.
Batch Alum Treatment
Batch alum treatment consists of applying high doses of alum (aluminum sulfate) to the surface
of a lake. The alum falls to bottom of the lake where it reacts with phosphorus to form an
aluminum-phosphorus precipitate that effectively seals the bottom sediments. The purpose of
batch alum treatment is to seal the sediments so that phosphorus is not released during anoxic
conditions. Under the proper conditions, one alum treatment may last eight years or more. Batch
alum treatment is appropriate for lakes with high internal phosphorus recycling and low external
phosphorus loads. Since Lake Carey has a high external phosphorus load, batch alum treatment
is not appropriate at this time. If, after septic system and stormwater runoff nutrient loads are
reduced, the lake is still too eutrophic, then batch alum should be considered for both the lake
and pond.
Continuous Alum Treatment
Continuous alum treatment consists of adding alum directly to the major tributary (or tributaries)
of a lake on a continuous basis. The purpose of continuous alum treatment is to remove
phosphorus from the water entering a lake. Alum is added to the stream in proportion to the flow.
Alum jar tests were performed during this study to determine the dose needed to reduce the
phosphorus concentration to a sufficient level. The results of the alum jar tests indicated that an
alum dosage of about 68 mg/l was sufficient to reduce the phosphorus concentration to 0.008
mg/l. This indicates that continuous alum treatment would effectively reduce the phosphorus
load entering Lake Carey from Meade Brook, the major tributary.
Continuous alum treatment should be further evaluated after progress has been made on reducing
the phosphorus loading from failing septic systems. If the lake is still too eutrophic, then
continuous alum treatment may also be needed.
7.6
Public Education
Public education is an important component of an effective management plan. The Lake Carey
Cottages Association has been conducting a public education program for two years under a
Growing Greener Grant. The current program includes a newsletter, distribution of PALM
Notes, and summer public lectures. The program focuses on such topics as septic system
management, riparian buffers, well water safety, and lake ecology.
The Lake Carey public education program should be expanded to include coverage of the
following topics:
1.
Stormwater Impacts on Lake Carey,
2.
Stormwater Management and Low Impact Development,
3.
Wastewater Management Options,
4.
Agricultural Best Management Practices,
5.
Homeowner Practices, and
6.
Lake and Watershed Management Plan
The education program should consist of fact sheets, displays, workshops, and school programs.
The audience for the public education program should include landowners and businesses in the
watershed, lake users, elected and appointed municipal officials, developers, farmers, and school
students. A website should be developed so that the management plan and educational
information can be posted. Many of these activities can be funded by grants from the Growing
Greener Program.
7.7
Water Quality Monitoring
A modified water quality program should be continued. It should consist of lake and stream
monitoring. Lake Carey should be monitored once per month from May through September. One
station should be in the lake and one in the pond. A surface water sample should be collected
from each lake station and analyzed for the following parameters:
Total Phosphorus
Dissolved Reactive Phosphorus
Total Nitrogen
Chlorophyll a
Total Suspended Solids
pH
Phytoplankton
In situ measurements should include Secchi Disk and a temperature-dissolved oxygen profile at
each station.
Quarterly dry and wet weather stream samples should be collected and analyzed for total
suspended solids, total phosphorus, and total nitrogen.
A formal baseline macrophyte survey should be conducted by a professional ecologist in order to
document the macrophyte species present and determine whether any of those macrophytes are
non-native, invasive species. If any invasive species are found, steps should be taken to eradicate
them immediately. Members of the Lake Carey Cottages Association should receive training in
the identification of the types of macrophytes found in Lake Carey as well as potential invasive
species so that they can conduct annual macrophyte surveys at the lake and pond. If in the future
the macrophyte populations become excessive, the Lake Carey Cottages Association should hire
a macrophyte management company to address the problem.
8.0
Implementation of Lake and Watershed Management Plan
8.1
Watershed Management Implementation
The two main priorities in watershed management for the Lake Carey watershed are managing
the damaging consequences of development: wastewater and stormwater. Implementing a
wastewater management program in the Lake Carey watershed should be a high priority.
Because the soils in the Lake Carey watershed have severe restrictions for conventional septic
systems, there is a high probability that all of the conventional septic systems in the Lake Carey
watershed are failing and are polluting the groundwater and Lake Carey. Therefore, replacement
or repair of the existing on-site wastewater systems is infeasible on a watershed scale.
Wastewater alternatives such as decentralized or centralized wastewater systems should be
evaluated as part of an Act 537 Plan revision for townships within the watershed.
The watershed stormwater problem areas identified in Section 5.0 should be corrected. These
problem areas consist of roads, culverts, gullies, drainage ditches, driveways, and unvegetated
lakeshore areas that contribute eroded soil and polluted stormwater to Lake Carey. Restoration of
eroding streambanks and installation or repair of drainage structures are highly successful ways
to significantly reduce sediment and nutrient loadings to Lake Carey for a reasonable cost. A
particularly low cost method for improving water quality in lakes and streams is to plant or
maintain a one to two foot unmowed vegetative buffer strip along all lake shores and
streambanks to ensure proper erosion control and to reduce the amount of nonpoint source
pollution entering the waterways.
The three problematic gravel roads in the Lake Carey watershed as noted in Section 7.3.1 should
be paved. Runoff from these roads should be directed to bioretention systems rather than to
storm sewers that discharge directly to Lake Carey.
Agricultural lands contribute significant amounts of sediment and nutrients to Lake Carey;
however, the Wyoming County Conservation District and the USDA Natural Resource
Conservation Service (NRCS) have already implemented many agricultural BMPs in the
watershed. These agricultural BMPs should be monitored to determine their effectiveness.
Nutrient Management and Conservation Management Plans are a high priority and should be
developed for all farms within the watershed. Riparian buffer zones on farmlands should be
restored as necessary to create a shrub and forested riparian zone along the tributaries to Lake
Carey. Farmer education and participation in the implementation of agricultural BMPs is
desirable since this practice will promote stewardship in the BMP. BMPs must be implemented
and maintained by the individual farmers in order to achieve the maximum benefit of the BMP.
8.2
Watershed Planning and Education Implementation
The Lake Carey watershed is developing rapidly. In order to preserve open space and protect the
water quality in Lake Carey, the townships in the watershed should update their zoning
ordinances and adopt riparian buffer, conservation, and stormwater management ordinances in
the near future. The existing public education program in the watershed should be expanded.
Local citizens should be educated about watershed protection practices and homeowner practices
that can help reduce nonpoint source pollution entering the lakes and streams.
8.3
In-Lake Management Implementation
In-lake management practices that should be considered for the pond and lake at Lake Carey
include: lake and pond dredging, lake aeration, and phosphorus inactivation (alum treatment).
Dredging the pond would be more economically feasible than dredging the lake, and should be a
priority. Hypolimnetic aeration is most applicable for the lake; the pond does not require aeration
due to its shallow nature. Continuous alum treatment is more applicable at Lake Carey than batch
alum treatment. All of these in-lake options would require feasibility studies to determine their
effectiveness.
In addition, a modified lake monitoring program should be continued in order to document any
improvements after implementing the lake and watershed management plan. A baseline
macrophyte survey should be performed to document the macrophyte distribution in the lake and
to detect any invasive species. Annual macrophyte surveys should follow.
8.4
Implementation Schedule
In-lake management alternatives such as phosphorus inactivation and hypolimnetic aeration are
important management techniques for Lake Carey, but should not be used in lieu of watershed
management practices. Until specific identified problems within the watershed are addressed,
nutrients and sediments will continue to enter the lake system and water quality will be
negatively impacted. In-lake alternatives should only be implemented after some or all of the
watershed management recommendations are implemented for greatest efficacy.
Implementation of the recommended management plan can be organized into short-term and
long-term action plans, as follows:
Short-Term Action Plan
The short-term action plan should consist of the following:
1.
Submit Growing Greener Application to:

Control Existing Stormwater Problem Areas

Expand Public Education Program

Develop Municipal Ordinances
2.
Implement Expanded Public Education Program
3.
Perform 537 Wastewater Management Plan Revision and Evaluate:

Decentralized Systems

Centralized Systems

Funding Sources
4.
Encourage Easements and Develop or Revise Existing Ordinances:

Conservation Easements

Riparian Buffer Ordinance

Conservation Ordinance

Stormwater Management Ordinance

Zoning Ordinance
5.
Investigate the Feasibility of Dredging the Pond and/or Spot Dredging of
the Pond and Lake
6.
Evaluate Funding Opportunities

Growing Greener Program

Penn Vest

Special Appropriations
7.
Continue Modified Water Quality Monitoring Program
Long-Term Action Plan
The long-term action plan is designed to be performed after progress has been made on reducing
the sediment and nutrient loadings from failing septic systems and watershed erosion and runoff.
Some elements of the long-term action plan could be performed concurrently with the short-term
action plan. The long-term action plan consists of the following:
1.
Investigate the Feasibility of Installing a Hypolimnetic Aeration System in
the Lake.
2.
Investigate the Feasibility of Adding Alum to Meade Brook to reduce the
phosphorus load to Lake Carey.
3.
Implement Dredging of Pond and/or Lake Based on Feasibility Study
8.5
Funding Sources
The two primary funding sources for implementing the recommended management plan are the
Pennsylvania Department of Environmental Protection (PA DEP) Growing Greener Program and
the EPA's 319 Nonpoint Source Program. The Growing Greener Program provides funding to
perform watershed protection programs, implement best management practices, and develop
public education programs. The 319 Nonpoint Source program is administered in Pennsylvania
through the Growing Greener Program, and provides funds for watershed management projects
and public education programs.
Another funding source is the Conservation Reserve Enhancement Program (CREP) which helps
to support the installation of conservation practices on farms through the Pennsylvania
Association of Conservation Districts (PACD). CREP is a federal program in which the U.S.
Department of Agriculture (USDA) partners with states to reduce sediment or nutrient runoff
from agricultural land. The USDA provides 50 percent of the funds necessary to install
conservation measures, such as filter strips, permanent vegetative cover or riparian buffers.
Additional funds come from the Growing Greener program. Farmers in the Lake Carey
watershed should be encouraged to apply for funding under the CREP program to implement
BMPs on their land.
9.0
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