Archers Creek Stormwater Plan Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Town of Emerald Isle/CWMTF ������������������ July 10, 2012
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Watershed Characteristics Watershed Characteristics • Archers Creek Is 3 Miles Long and Runs East/West with • Archers Creek Is 3 Miles Long and Runs East/West with the Divide at Old Ferry Road the Divide at Old Ferry Road • Watershed Area Is ~500 Acres • Watershed Area Is ~500 Acres � Mix of Residential and Commercial Land Use � Mix of Residential and Commercial Land Use • Water Quality Is an Issue • Water Quality Is an Issue � Both Sides Discharge to Bogue Sound (SA and ORW � Both Sides Discharge to Bogue Sound (SA and ORW Classification – Very High Standard) Classification – Very High Standard) � Fecal Coliform Is the Main Contaminant of Concern � Fecal Coliform Is the Main Contaminant of Concern � Only Area of Town Where Water Quality Use Is “Not Supported” � Only Area of Town Where Water Quality Use Is “Not Supported” � NCDEH Monitoring Data � NCDEH Monitoring Data � Town Received CWMTF Grant to Complete Study to Develop � Town Received CWMTF Grant to Complete Study to Develop Options to Improve Water Quality Options to Improve Water Quality
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Watershed Characteristics Watershed Characteristics
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Data Collection Data Collection • Rainfall – NOAA Website • Rainfall – NOAA Website • Soils – USDA Website • Soils – USDA Website • Topography • Topography � Mix of State LIDAR and Joyner Keeny Survey of Pipe Networks � Mix of State LIDAR and Joyner Keeny Survey of Pipe Networks • Land Use • Land Use � County GIS Data � County GIS Data � Mix of Residential, Manufactured Home, Commercial and � Mix of Residential, Manufactured Home, Commercial and Undevelopable Areas Undevelopable Areas � Approaching Full-Buildout Conditions � Approaching Full-Buildout Conditions • Water Quality • Water Quality � NCDEH Data at Two Creek Mouths & Data Collected Along Creek � NCDEH Data at Two Creek Mouths & Data Collected Along Creek To Help Determine Potential Issues and Prioritize Sites To Help Determine Potential Issues and Prioritize Sites
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Data Collection Data Collection
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Water Quality Data Water Quality Data • Location of the Sampling Station within Sound for • Location of the Sampling Station within Sound for NCDEH Data Has a Big Effect on Results NCDEH Data Has a Big Effect on Results • West Site Nearly Always Meets Standard • West Site Nearly Always Meets Standard NCDEH Fecal Coliform Data (West Watershed) 140 130 120 110 100 90 Fecal Coliform (Col/100 mL) 80 70 60 50 40 30 20 Standard=14 col/100 mL 10 0 9/20/2002 9/20/2003 9/19/2004 9/19/2005 9/19/2006 9/19/2007 9/18/2008 9/18/2009 9/18/2010 Date
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Water Quality Data Water Quality Data • East Site More Variable – Better Towards Mouth • East Site More Variable – Better Towards Mouth NCDEH Fecal Coliform Data (East Watershed) 375 350 325 300 275 250 Fecal Coliform (Col/100 mL) 225 200 175 150 125 100 75 50 Standard=14 col/100 mL 25 0 10/21/1992 10/21/1994 10/20/1996 10/20/1998 10/19/2000 10/19/2002 10/18/2004 10/18/2006 10/17/2008 10/17/2010 Date Station 30 Station 30A Station 30B
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Water Quality Data Water Quality Data • No Sampling Available for Creek So M&N Completed • No Sampling Available for Creek So M&N Completed Detailed Sampling Detailed Sampling • However, Only for One Event Due to Time and Budget • However, Only for One Event Due to Time and Budget Constraints – Supply at Least a “Snapshot” Constraints – Supply at Least a “Snapshot” • Results Were Mixed • Results Were Mixed � TKN and TSS Were Below Typical Stormwater Concentrations � TKN and TSS Were Below Typical Stormwater Concentrations � Nitrate/Nitrite, Phosphorus, Fecal Coliform and Enterococci � Nitrate/Nitrite, Phosphorus, Fecal Coliform and Enterococci Were Above Typical Concentrations Were Above Typical Concentrations • Points to Possible Surfacewater and Groundwater • Points to Possible Surfacewater and Groundwater Sources Sources � Fertilizer Runoff, Wildlife, Possible Septic Tank Failures � Fertilizer Runoff, Wildlife, Possible Septic Tank Failures
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Water Quality Data Water Quality Data
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Water Quality Data Water Quality Data
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Water Quality Data Water Quality Data Total Kjeldahl Nitrogen (TKN) 4.00 West Watershed East Watershed 3.75 3.50 3.25 3.00 2.75 2.50 2.25 TKN (ppm) 2.00 1.75 1.50 Typical Stormwater Concentration=1.4 mg/L 1.25 1.00 0.75 0.50 Total Suspended Solids (TSS) 0.25 West East 0.00 50 Typical Stormwater Concentration=50mg/L West Watershed East Watershed 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Site Number 45 40 35 30 TSS (ppm) 25 20 15 10 5 West East 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Site Number
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Water Quality Data Water Quality Data Nitrate/Nitrite Nitrogen (NO 3 -N) 4.00 West Watershed East Watershed 3.75 3.50 3.25 3.00 2.75 2.50 NO 3 +NO 2 -N (ppm) 2.25 2.00 1.75 1.50 1.25 1.00 0.75 Typical Stormwater Concentration=0.6 mg/L 0.50 0.25 Total Phosphorus (TP) East West 0.00 2.00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 East Watershed West Watershed Site Number 1.75 1.50 1.25 TP (ppm) 1.00 0.75 0.50 Typical Stormwater Concentration=0.2-0.3 mg/L 0.25 West East 0.00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Site Number
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Water Quality Data Water Quality Data Fecal Coliform 5000 West Watershed East Watershed 4750 4500 4250 Typical Stormwater Concentration>4000 mg/L 4000 3750 3500 3250 Fecal Coliform (col/100mL) 3000 2750 2500 2250 2000 1750 1500 1250 1000 750 Enterococci 500 Human Health Standard=14 mg/L 5000 West Watershed East Watershed 250 West East 4750 0 4500 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 4250 Site Number 4000 3750 3500 3250 Enterococci (col/100mL) 3000 2750 2500 2250 2000 1750 1500 1250 1000 750 500 Human Health Standard=35 mg/L 250 West East 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Site Number
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Development of Potential BMPs Development of Potential BMPs • Broken Into Three (3) Zones: Western, Central, Eastern • Broken Into Three (3) Zones: Western, Central, Eastern • Zones Based On Watershed Characteristics and BMP • Zones Based On Watershed Characteristics and BMP Opportunities Opportunities • BMPs Ranged From Simple Culvert Removal to Large • BMPs Ranged From Simple Culvert Removal to Large Scale Expensive BMPs with Land Purchase Required Scale Expensive BMPs with Land Purchase Required � Based On Water Quality Data and Watershed Assessment, � Based On Water Quality Data and Watershed Assessment, Infiltration and Filtration BMPs Show Most Promise Infiltration and Filtration BMPs Show Most Promise � Hydraulic Modification to Allow More Flushing Also Is Promising � Hydraulic Modification to Allow More Flushing Also Is Promising But May Have Habitat Change and Adjacent Resident Concerns But May Have Habitat Change and Adjacent Resident Concerns
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Western Zone Western Zone • Culvert Replacements Along Main Creek to Improve • Culvert Replacements Along Main Creek to Improve Tidal Flushing Tidal Flushing • Infiltration BMP at Emerald Plantation Townhomes • Infiltration BMP at Emerald Plantation Townhomes • Emerald Plantation Shopping Center (Catch Basin • Emerald Plantation Shopping Center (Catch Basin Inserts or Underground Infiltration/Storage Inserts or Underground Infiltration/Storage • Removal of Selected Woodpecker Lane Culverts • Removal of Selected Woodpecker Lane Culverts • Reed Drive/Boardwalk Avenue Bioretention/Wetland • Reed Drive/Boardwalk Avenue Bioretention/Wetland • Marsh and Buffer Restoration Throughout • Marsh and Buffer Restoration Throughout
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Western Zone Western Zone
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Western Zone Western Zone
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Western Zone Western Zone
Archers Creek Stormwater Plan Town of Emerald Isle/CWMTF Western Zone Western Zone
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