nutt pond watershed restoration
TRANSCRIPT
NUTT POND
WATERSHED
RESTORATION CITY OF MANCHESTER
STORMWATER MANAGEMENT
PROGRAM
NUTT POND
Nutt Pond is one of 6 urban ponds
located in Manchester, NH
NH DES & the City monitor these urban
ponds with help from the Volunteer Lake
Assessment Program (VLAP)
The City of Manchester started the Nutt
Pond study in 2005 through the
Supplemental Environmental Project
Program as part of the on-going CSO
separation efforts.
NUTT POND AREA OVERVIEW
Location: Driving Park Road, off of South Willow Street in south Manchester.
NUTT POND WATERSHED
Watershed Area: 635
Acres
Watershed is broken
into 4 subwatersheds
based on inlet locations.
One natural inlet
(Tannery Brook) &
three storm drain inlets
Highly Urbanized
Land Use: Commercial
& High Density
Residential
Approximately 60%
Impervious
WATERSHED RESTORATION
PLAN In 2002, Nutt Pond was placed on the NH 305(b)/303(d) list based on
chlorophyll-a levels, limiting primary contact recreation. It was also listed for
Non-Native Aquatic Plants.
In subsequent years it was also listed based for phosphorus, chlorides, pH and
dissolved oxygen levels.
WATERSHED RESTORATION
PLAN
The City prepared a Watershed Restoration Plan to determine existing
pollutant loading, select BMPs and identify pollutant removals that would
help reach long term water quality goals.
Problem: It was determined that approximately 125 lbs/yr of TP and 47 tons
/ year of TSS enter Nutt Pond via Stormwater
WATERSHED RESTORATION
PLAN
It was estimated that the average phosphorus levels in Nutt Pond were 0.028 mg/L
It was determined that a water quality goal of 0.015 mg/L should be the target for
long-term “in-pond” phosphorus concentration in order to reduce chlorophyll-a levels.
This would require a decrease in total annual phosphorus loading from 161 pounds
(124 lbs stormwater) to 86 pounds. A reduction of 75 lbs/yr.
WATERSHED RESTORATION
PLAN
Solution:
Decrease TSS & TP Loading = Decreased Nutt Pond chlorophyll-a
levels
Select BMPs to target TSS & TP removal
BMP SELECTION
Example of the BMP Ranking Process:
Select BMPs that will fit on a
site and allow maintenance to be performed.
Rank the BMPs based on the information below.
Cost of the BMP.
The highest removal efficiency for the contaminant that you are trying to remove.
The least cost per pound for the contaminant that you are trying to remove.
Select the BMPs that are implementable, within the dollar amount allotted for the project and that rank the highest based on the above information.
BMP SELECTION
NO SINGLE BMP
WILL SOLVE
ALL YOUR
PROBLEMS.
YOU MAY
NEED TO PAIR
UP BMPs TO
GET THE
DESIRED
RESULTS.
THIS WOULD ALSO
INCLUDE
PUBLIC
EDUCATION
AND OTHER
NON-
STRUCTURAL
BMPS
SAND REDUCTION PROGRAM
SAND REDUCTION PROGRAM
WATERSHED RESTORATION
PLAN
2005 – City of Manchester awarded 319s grant funding to
complete study and Phase 1 BMPs
2006 – Completion of Watershed Restoration Plan.
Summer 2006 – Completion of the East Inlet BMP.
Fall 2006 – Completion of the North & South Inlet
Retrofits.
Fall 2006 – Completion of the West Bank Stabilization BMP
Summer 2007 – Completion of the South Inlet BMP
Summer 2010 – Completion of the Woodgate Court
Drainage & Stabilization BMPs
2011 - City of Manchester awarded 319s grant funding to
complete study and Phase 2 BMPs
NUTT POND INLET
IMPROVEMENTS SITES
SITE 1 – NORTH INLET
SITE 2 – SOUTH INLET
SITE 3 – EAST INLET
SITE 4 – SOUTH INLET (HENRY’S)
SITE 5 – WEST BANK STABILIZATION
SITE 6 – WOODGATE COURT
NORTH INLET SITE 1
NORTH INLET SITE 1
SOUTH INLET SITE 2
EAST INLET SITE 3
EAST INLET SITE 3
EAST INLET SITE 3
EAST INLET SITE 3
EAST INLET SITE 3
SOUTH INLET (HENRY’S) SITE 4
SOUTH INLET (HENRY’S) SITE 4
SOUTH INLET (HENRY’S) SITE 4
SOUTH INLET (HENRY’S) SITE 4
WESTBANK STABILIZATION SITE 5
WOODGATE COURT SITE 6
10’ DIA. DEEP SUMP DMH
UPSTREAM HEADWALL
ROCK CROSS VANE
CHANNEL
ADDITIONAL DRAINAGE
ADDITIONAL DRAINAGE
OUTLET GRATE
PROJECT COSTS
Project (Phase) Total Cost Grant Funding
Nutt Pond Phase 1 Grant $599,000 $60,000
Woodgate Court
(construction only) $366,000 $0
Nutt Pond Phase 2 Grant
(anticipated) $350,000 $174,000
Totals $1,131,500 $234,000
WEST INLET PROPOSED SITE 7
WEST INLET PROPOSED SITE 7
Source: UNH Stormwater Center Website: http://www.unh.edu/unhsc/
EAST INLET PROPOSED SITE 8
EAST INLET PROPOSED SITE 8
Source: UNH Stormwater Center Website: http://www.unh.edu/unhsc/
WATERSHED PLAN SUCCESS
Estimated BMP removals to date:
East Inlet ~ 185 cubic yards of sediment
South Inlet ~ 145 cubic yards of sediment
Woodgate Court Channel (East Inlet) ~ 4,500 cubic yards of sediment
Woodgate Court BMPs (East Inlet) ~ 6 cubic yards of sediment
Since 2008, approximately 4,836 cubic yards removed (~ 1,200 Cy/Yr)
WATERSHED PLAN SUCCESS
Phosphorus Levels:
WATERSHED PLAN SUCCESS
Chlorophyll a levels:
MORE INFORMATION
Websites
Stormwater http://www.manchesternh.gov/CityGov/dpw/EPD/stormwater/home.html
SEPP (Supplemental Environmental Projects Program) http://www.manchesternh.gov/CityGov/DPW/EPD/SEPP/Home.html
Contact Information:
Robert Robinson, P.E. Environmental Permits Coordinator City of Manchester Department of Highways Environmental Protection Division 300 Winston Street Manchester, NH 03103 Ph: 603-624-6513 Fax: 603-628-6234 Cell: 603-235-6630 E-mail: [email protected]
Benjamin Lundsted, P.E. Environmental Engineer Comprehensive Environmental, Inc. 21 Depot Street Merrimack, NH 03054 Ph: 603-424-8444 Fax: 603-424-8441 Cell: 800-725-2550 E-mail: [email protected]