Stormwater Quality & LID for Ephemeral Watersheds. Marie Light April 9th, Low Impact Development Workshop

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1 Stormwater Quality & LID for Ephemeral Watersheds Marie Light April 9th, Low Impact Development Workshop

2 2 Topics Surface Water Quality Standards Ephemeral Aquatic Communities Natural Processes in LID Pima County Examples Sustainability Plan Pima Prospers Ordinance : GI/LID Amendments

3 Methods keeping stormwater clean Part 1 1. Eliminate discharge of pollutants into navigable waters 2. Attain water quality protective of the following: Fish, shellfish and wildlife Recreation in and on the water 3. Prohibit discharge of toxic pollutants in toxic amounts 1972 Federal Water Pollution Control Act Amendments, codified as 33 USC 1251(a)(1)-(3) 3

4 4 Methods keeping stormwater clean Part 2 4. Provide federal funds to construct POTWs for wastes 5. Develop State programs to control pollutant sources 6. Develop technology eliminating pollutant discharges 7. Control non-point sources 402 NPDES AZPDES MS4 permits with LID 1972 Federal Water Pollution Control Act Amendments, codified as 33 USC 1251(a)(4)-(7)

5 What is protected by the regulations here in Pima County? Fish, shellfish and wildlife 1,2 (Santa Congress; Tanque Houghton; Vail;.. Cienega Station Rd) Green sunfish, Longfin dace, mosquito fish No shellfish Red-spotted Toad, North American Bullfrog, Couch s Spadefoot Toad Microinvertebrates that are food for others or facilitate decomposition of detritus Macroinvertebrates Arid West Water Quality Research Project 1 Habitat Characterization Study Final Report (Pima county, 2002) 2 Aquatic Communities of Ephemeral Stream Ecosystems (Pima County, 2006) 5

6 What is protected by the regulations here in Arizona? Recreation in and on the water Birding, $2 billion/year income to Arizona 1 Boating, skiing, fishing on lakes & swimming Water sources Drinking water systems 2 (wells, surface water) Agriculture (irrigation and livestock) 1 Economic Impacts of wildlife watching (Tucson Audubon Society, 2011) 2 R Groundwater Under the Direct Influence of Surface Water; ARS

7 Methods to protect Designated Uses LAKE AQUATIC&WILDLIFE HUMAN HEALTH AGRI. FBC Full Body Contact DWS Domestic Water Source AgI Agricultural Irrigation PBC Partial Body Contact FC Fish Consumption AgL Agricultural Livestock Watering A.A.C. R and Appendix B. Surface Waters and Designated Uses 7

8 Designated Uses in Eastern Pima county No Aquatic & Wildlife Fish Consum ption Body Contact 1 Warm water Full 2 Warm water Full 3 Warm water Full 4 Ephemeral Partial 5 Ephemeral Partial 6 Effluent dependent Partial Dom. H 2 O Agricultural Livestock watering Irrig & Livestock watering Livestock watering Livestock watering Livestock watering Stormwater Management Program AZPDES Permit No. AZS (Pima County, 2014) 8

9 40 CFR (d) Water Quality Standards and State Requirements A.A.C. R and Appendix A. Numeric Water Quality Standards 9

10 10 Surface Water Sampling and Arizona Results Monitored Parameters Results Microbial E. Coli Nutrients (nitrogen & phosphorus) Non-detect or below standards Cyanide Non-detect or below standards Other metals Copper, lead, zinc VOCs & Semi-VOCs Occasional VOCs & SVOC detections PCBs/Pesticides Residual of products not manufactured Total Suspended Solids Trash Note: MS4s in more urbanized areas detect residual herbicides and pesticides

11 LID Natural Processes Enhancing Water Quality 11

12 12 Water Quality Improvements by LID Effective reduction or removal by tailoring to site conditions Nutrients Low concentration metals Trash Sediment Ineffective reduction or removal Solvents or organic compounds Large volumes of pollutants Highly toxic compounds

13 13 Upgrades to Wastewater Treatment Plants Before Aqua Nueva WRF After Agua Nueva WRF Foamy, black-colored water Non-foamy, clear water

14 Stormwater Harvesting System Ordinance Updates Water conservation measures Rainwater harvesting systems in all zones Standard language LID shall be used in Conservation subdivision Small Shopping Centers Off-street parking and loading Stormwater harvesting specs Effective April 17,

15 Pima Prospers Pima County Comprehensive Plan Initiative Land use with LID principles Conservation Land System Stormwater as a water source Reduce runoff & flooding Cost of Development Goals & Polices Explore recovery of costs by using LID in parks, flood control, and other facilities Special projects Use stormwater to irrigate hydroriparian and mesoriparian areas on a road project 15

16 16 Pima County 5 Year Sustainability Plan Invested $412,475 Dunbar Spring Traffic Calming, Water Harvesting & Street Beautification Stormwater irrigates native trees & bushes Project provides Natural shaded walkways Wildlife habitat Increased safety & mobility Enhances quality of life

17 Water Right to Rainfall on Your Roof Western water law = prior appropriation (First it time, first in line to take water) Transition Zone/ Colorado Plateau (perennial flows) Surface water recharges ground water Harvested water reduces downstream flow Worry about impact to future water supplies Basin & Range Desert (ephemeral flows) Imported surface water supplements groundwater Harvested stormwater Irrigates native vegetation Increases natural shade Stormwater harvesting is incentivized 17

18 Re-establish Natural Hydrologic Functions 10% Runoff 55% Runoff 15% Runoff 15% Runoff 50% Infiltration 10% Infiltration 45% Infiltration 45% Infiltration 18

19 19 Tell me how likely you would be to take part (very likely, somewhat or not at all) in activities people can do to keep storm water clean. 0% 20% 40% 60% 80% 100% Safely dispose of chemicals If you have a dog, using a doggie bag to clean up after them Report a spill Very Likely Somewhat Likely Not At All Likely Replacing a toxic compound with a nontoxic compound Implement Low Impact Development practicies FMR, Fig 34

20 20 Tell me if the listed Low Impact Development practice has been implemented or installed at your home or business Landscaping w/native plants Landscaped depressions that collect stormwater Connecting runoff from roof/paved surface to 0% 20% 40% 60% 80% 100% Porous pavements or bricks Natural areas protected from clearing and grading Water harvesting using rain barrels or cisterns Gravel-filled trench to collect storm water Other Not sure/don t know FMR, 2014, Fig. 29

21 21 Stormwater is a resource to be well managed Restore natural hydrologic functions by reducing imperviousness and watering native vegetation Improve water quality with nutrient recycling, sedimentation, filtration, soil & microbial decomposition Marie Light Pima County Department of Environmental Quality Stormwater Manage Program Marie.light@pima.gov