Truesdale Lake  

South Salem, New York

Stormwater Management Projects

Lake Truesdale Stormwater Management Project Descriptions & Cost Estimates

Summary of Sites

The original Lake Study was delivered on September 4, 2001 and documented these six sites and outlined steps the lake community could take to make the lake better.

Land-Tech made a presentation in April 2002 to the lake community.  This presentation is available here.

You can download the original document below in MS Word format by clicking here (some modifications have been made to the document pages below since the original document was published in 2005).

Figure: Map of Sites

<– North

Summary Map of 6 Potential Stormwater Improvement Sites

Summary Map of 6 Potential Stormwater Improvement Sites

Site Descriptions 1-6 follow.

SITE #1
Description of Work:
This site is near the south end of the lake at a location where the town has previously installed a hydrodynamic separator. The proposed work includes excavating road sand and other sediment that has accumulated at the shoreline. Once the sediment is excavated, the excavation is to be enlarged and formalized by the addition of a boulder wall to form a “forebay” to trap and store sediment before it can enter the lake. In the road, a new section of curb and a catch basin are proposed to intercept stormwater runoff. The immediate shallow water area beyond the forebay is to be planted with emergent aquatic vegetation for stabilization, nutrient uptake and habitat enhancement. All disturbed land areas are to be stabilized with topsoil and seed.
Benefits of work:
Stormwater runoff will be treated by a treatment train comprised of sediment trapping in catch basin sumps, additional sediment and “floatable” trapping by the hydrodynamic separator, and still more sediment trapping in the forebay. With proper maintenance, to ensure that trapped sediment is not re-suspended and carried into the lake, the amount of sediment discharged to the lake, along with the amount of nutrients adsorbed to the sediment, will be substantially reduced.
Cost of work:
Our estimated capital cost is $22,000, to which a contingency factor and administrative expenses should be added.
Duration of work:
All work at this site can be completed within a week to ten days.

SITE #2
Description of Work:
This site is immediately adjacent to Site #1 at the south end of the lake. The proposed work includes replacing existing drainage pipes with properly sized pipes, adding better catch basins, making minor alterations to pavement and curbing, and installing a hydrodynamic separator. All disturbed land areas are to be stabilized with topsoil and seed.
Benefits of work:
This work is intended to intercept runoff before it reaches the lake and direct it through the hydrodynamic separator for removal of sediment and floatable materials. The work will also help reduce erosion between the pipe discharge and the edge of the lake. Both effects will reduce the amount of sediment and adsorbed nutrients discharged to the lake.
Cost of work:
Our estimated capital cost is $70,000, to which a contingency factor and administrative expenses should be added.
Duration of work:
All work at this site can be completed within thirty days.

SITE #3
Description of Work:
Work at this site includes improvements to two major drainage paths flowing to the lake. The northern drainage path work begins with the stabilization (stone lining plus check dams) of a severely eroded hillside ditch followed by roadside drainage improvements. Additional eroded ditch stabilization followed by a stabilized outlet at the lake complete the proposed work along this drainage path. All disturbed land areas are to be stabilized with topsoil and seed.
The southern drainage path work involves replacing a section of storm drainage pipe, installing a hydrodynamic separator at the top of the beach driveway, excavating sediment deposits from the shoreline area, and creating a forebay in the shoreline excavation area. The immediate shallow water area beyond the forebay is to be planted with emergent aquatic vegetation for stabilization, nutrient uptake and habitat enhancement. All disturbed land areas are to be stabilized with topsoil and seed.
Benefits of work:
This project is intended to reduce the discharge of sediment and adsorbed nutrients to the lake. This is accomplished by reducing the active erosion in the channels forming the northern drainage path. Providing additional hydraulic capacity in the storm drainage reduces the frequency of road overtopping and resultant driveway washouts in the area of the northern drainage path. In the southern drainage path, the sediment removal is to be accomplished by sediment trapping in catch basin sumps, the hydrodynamic separator and the forebay.
Cost of work:
Our estimated capital cost is $150,000, to which a contingency factor and administrative expenses should be added.
Duration of work:
A contractor can complete this work in 30-45 days.

SITE #4
Description of Work:
This is a substantial maintenance project. There are no new erosion controls or other treatment facilities involved. The work involves excavating approximately 3200 cubic yards of sediment from an impoundment to restore its sediment trapping capability.
Benefits of work:
When the area around this site was originally developed, the work included the formation of a long (more than 1200 feet long) impoundment of the watercourse draining from Pumping Station Swamp to Truesdale Lake. One purpose of this impoundment was to trap sediment transported by the watercourse, The local project approval included provision for periodic maintenance for removal of sediment from the impoundment.
This project proposes such sediment removal, because the impoundment is at capacity and no longer provides sediment trapping. The benefit of the work proposed at this site is that restoration of the sediment trapping and storage capacity of the original impoundment will reduce the discharge of the sediment carried by the watercourse to Truesdale Lake. The amount of sediment can be substantial during a severe storm, as the watershed is on the order of three square miles.
Cost of work:
Our estimated capital cost is $150,000, to which a contingency factor and administrative expenses should be added.
Duration of work:
This project could be completed in as little as 45 days if the sediment will dewater quickly to allow transport without stockpiling and delay and if a nearby disposal area is available. More likely is that the project will be completed in phases and take much longer to complete.

SITE #5
Description of Work:
This site is a boulder-strewn drainage corridor. The work proposed involves stabilizing the area from the end of a storm drain to the lake by lining the channel with vegetation and constructing a forebay at the water’s edge. The immediate shallow water area beyond the forebay is to be planted with emergent aquatic vegetation for stabilization, nutrient uptake and habitat enhancement. All disturbed land areas are to be stabilized with topsoil and seed.
Benefits of work:
The project will reduce erosion along the drainage path and will provide additional sediment trapping to reduce the amount of sediment and adsorbed nutrients entering the lake.
Cost of work:
Our estimated capital cost is $15,000, to which a contingency factor and administrative expenses should be added.

Duration of work:
The work can be completed in a week to ten days.

SITE #6
Description of Work:
Work at this site involves stabilization of a small area at the outlet of a storm drainage pipe. The project also involves construction of a new section of curb and a catch basin to intercept stormwater runoff, installing a hydrodynamic separator, excavating sediment deposits from the shoreline area, and creating a forebay in the shoreline excavation area. The immediate shallow water area beyond the forebay is to be planted with emergent aquatic vegetation for stabilization, nutrient uptake and habitat enhancement. All disturbed land areas are to be stabilized with topsoil and seed.
Benefits of work:
Stormwater runoff will be treated by a treatment train comprised of sediment trapping in the catch basin sump, additional sediment and “floatable” trapping by the hydrodynamic separator, and still more sediment trapping in the forebay. With proper maintenance, to ensure that trapped sediment is not re-suspended and carried into the lake, the amount of sediment, along with the amount of nutrients adsorbed to the sediment, will be substantially reduced.
Cost of work:
Our estimated capital cost is $82,000, to which a contingency factor and administrative expenses should be added.
Duration of work:
A contractor can complete this work in 30-45 days.

2 Comments

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