The Watershed Connection

Stormwater Management: LID Practices | 2

19941994

Stormwater Management: LID Practices | 3

19991999

Stormwater Management: LID Practices | 4

20042004

Stormwater Management: LID Practices | 5

Development ProcessDevelopment Process

• Compacts soils, reduces infiltration, increases impervious area and runoff

• Disturbs soils by adding fill, burying fertile soil layers and leaving behind poor quality soil.

• Poor soil growing conditions promotes use of fertilizer and irrigation

• Rainfall runoff is conveyed to centralized stormwater system often marketed as lake front property.

Impervious

Fertilized Turf

Unfertilized Turf “Row Crop”

Undisturbed

Visualization of Land Use Connection

Visualization of Land Use Connection

Impervious Fertilized Turf Unfertilized Turf

“Row Crop” Undisturbed

Stormwater Management: LID Practices | 8

Watershed Connection Watershed Connection

Stormwater Management: LID Practices | 9

Oligotrophic - Low Water Column Nutrients

Oligotrophic - Low Water Column Nutrients

•Low water column nutrients•Clear water•Some plants and algae but low numbers

Stormwater Management: LID Practices | 10

Mesotrophic - Medium Water Column Nutrients

Mesotrophic - Medium Water Column Nutrients

•Low water column nutrients•Nutrients flux from sediment•Mostly clear water•Bottom algae grows in shallower water•Algae breaks loose and floats

Stormwater Management: LID Practices | 11

Eutrophic / Hypereutrophic – High Water Column NutrientsEutrophic / Hypereutrophic – High Water Column Nutrients

•High nutrients in water column•Support growth of diatoms and plankton•Green Cloudy Water•Few bottom plants – light limited

Stormwater Management: LID Practices | 12

Sources of NutrientsSources of Nutrients

• Fertilizer application• Runoff sediments• Irrigation water• Atmospheric Deposition• Soil leaching• Plant debris• Waterfowl• Internal nutrient cycling

Stormwater Management: LID Practices | 13

Reclaimed Water UseReclaimed Water Use

• Reclaimed water used to irrigate Golf Course and Common areas

• Excellent conservation measure to protect high quality groundwater – however

• Nutrient levels in reclaimed water are quite high compared to typical irrigation sources

• Nutrient additions should be accounted for and fertilizer applications should be adjusted accordingly.

• Extra care should be given to issues of overspray, broken heads etc.

Stormwater Management: LID Practices | 14

Reclaimed Water Use 2008Reclaimed Water Use 2008

• CDD Common Areas 81,703,900 gal• Golf Course 158,856,071gal

• Nutrient concentration in reclaimed water 9.2 mg/l nitrogen (0.035-0.890 ppm in ponds) 4.6 mg/l nitrogen (0.013-0.590 ppm in ponds)

• “Free” fertilizer from reclaimed water 2.04 lbs/1000 sq ft of N 1.02 lbs / 1000 sq ft of P

Stormwater Management: LID Practices | 15

Additional phosphorus sourceAdditional phosphorus source

• Rid-O-Rust Chelating agent for iron to reduce stains Source of phosphorus

Stormwater Management: LID Practices | 16

Overall SummaryOverall Summary

• Significant changes to hydrology, soils and water chemistry due to development.

• Stormwater ponds collect all runoff from adjacent watershed

• Stormwater ponds are equivalent to lakes and will respond to nutrients the same way

• Major nutrient sources are fertilizer, reclaimed water and soils

• Significant effort to reduce nutrient loads to pond is requred.