Stormwater Management Steps Module 3: Stormwater Effects and Pollutant Sources • Identify beneficial use impairments • Identify causes of impairments Robert Pitt, P.E., Ph.D., DEE • Identify sources (magnitude, seasonality, Department of Civil and Environmental Engineering flow phases, etc.) of problem constituents The University of Alabama • Identify, select, and design controls Presentation based on material further discussed in: Burton, G.A. Jr., suitable for problem pollutants and and R. Pitt. Stormwater Effects Handbook: A Tool Box for Watershed Managers, Scientists, and Engineers . ISBN 0-87371-924-7. CRC Press, locations Inc., Boca Raton, FL. 2002. 911 pages. • Implement controls, conduct validation monitoring, modify controls as needed Photo by Lovena, Harrisburg, PA Major Receiving Water Beneficial Uses • Stormwater Conveyance (flood prevention) • Recreation (non-water contact) Uses • Biological Uses (Warm water fishery, aquatic life use, biological integrity, etc.) • Human Health Related Uses (Swimming, Fishing, and Water Supply) WI DNR photo 1
Basic Goals for Urban Streams • Certain basic stormwater controls at the time of development, plus protection of stream • Stormwater conveyance and aesthetics should habitat, may enable partial use of some of be the basic beneficial use goals for all urban waters. these goals in urbanized watersheds. • Biological integrity should also be a goal, but • Water contact recreation, consumptive with the realization that the natural stream fisheries, and water supplies are not ecosystem will be severely modified with appropriate goals for most heavily urbanized urbanization. watersheds. – “Biological integrity is the capacity to support and maintain a balanced, integrated and adaptive biological system having the full range of elements [the form] and process [the function] expected in a region’s habitat.” James Karr 1991, modified Receiving Water Effects of Historical concerns focused on increased flows during rains and associated flooding. However, decreased flows during dry Water Pollutant Discharges periods are now seen to also cause receiving water problems. • Sediment (amount and quality) • Habitat destruction (mostly through high flows [energy] and sedimentation) • Eutrophication (nutrient enrichment) • Low dissolved oxygen (from organic materials) WI DNR photo • Pathogens (mostly from municipal wastewater and agricultural runoff) • Toxicants (heavy metals and organic toxicants) • Temperature • Debris and unsafe conditions • etc. 2
Sediment transported in stormwater causes significant receiving water impacts . WI DNR photo WI DNR photos Bank instability and habitat destruction due to increased flows R. Bannerman photo One Early Method of Getting Rid of Wastewater Wastewater treatment has only been around since the late 1800s. People dumped wastes into gutters and ditches, or sometimes out an open window. Wastes then flowed into nearest stream or pond. “Sewer” is from the old English meaning seaward. Coombs and Boucher 3
Polluted New York Harbor in 1883 Coombs and Boucher Gross floatables most important wet weather Basic Wastewater Conveyance in Sanitary flow pollutant in many urban areas. Condition not Always Achieved McKinney and Schoch 4
Sewage contamination of storm drainage system Beach Closings in the US in 1994 ( Water Envir. & Tech . 1995) Sanitary Sewer Overflows (SSOs) 584 (43%) Stormwater Runoff 345 (25%) Combined Sewer Overflows (CSOs) 194 (14%) Agricultural Runoff 136 (10%) Wastewater Treatment Plant 106 (7.8%) Malfunctions Children frequently play in urban creeks, irrespective Public swimming beach located in utility right-of-way of their designation as water contact recreation waters adjacent to stormwater outfall (not uncommon) WI DNR photo 5
Historical approach to urban drainage has been devastating to Fishing in urban waters also occurs, both for environment and recharge of groundwaters recreation and for food. WI DNR photo WI DNR photo WI DNR photo 6
WI DNR photos Eutrophication dramatically detracts from recreational uses, along with affecting aquatic life Cuyahoga River in Cleveland Often Caught Inappropriate discharges, including on Fire Between 1952 and 1969 accidental hazardous material releases, into storm drainage can cause acute receiving water effects. Coombs and Boucher 7
Fire from 200,000 gallons of spilled gasoline in residential area from pipeline rupture (June 1999) Bellingham Herald (Washington) Whatcom Creek, Bellingham, WA, fire-fighting foam Alabama has about 200 transportation accidents Groundwater Contamination a year involving hazardous materials. This is The potential for groundwater contamination associated typical for most states. with stormwater infiltration is often asked. Road cut showing direct recharge of Edwards Aquifer, Austin, TX Book published by Ann Arbor Press/CRC, 219 pages. 1996, based on http://civil.eng.ua.edu/~rpitt/Publications/BooksandReports/ EPA research and NRC Groundwater%20EPA%20report.pdf Birmingham News (Alabama) committee work. 8
Barton Springs, Austin, TX Example Weak-Link Model Influencing Factors Constituent Abundance in Mobility Filterable Stormwater (sandy/low Fraction organic soils) (treatability Nitrates low/moderate mobile high Chlordane moderate intermediate very low Anthracene low intermediate moderate Pyrene high intermediate high Lead moderate very low very low Links Depend on Infiltration Method Moderate to High Groundwater Contamination Potential (contamination potential is the lowest rating of the Surface Infiltration Surface Infiltration Injection after with no after Sedimentation Minimal influencing factors) Pretreatment Pretreatment • Surface infiltration with no pretreatment (grass Lindane, chlordane Lindane, chlordane swales or roof disconnections) Benzo (a) anthracene, bis Fluoranthene, pyrene 1,3-dichlorobenzene , – Mobility and abundance most critical (2-ethylhexl phthalate), benzo (a) anthracene, bis • Surface infiltration with sedimentation fluoranthene, (2-ethylhexl phthalate), pretreatment (treatment train: percolation pond pentachlorophenol, fluoranthene , phenanthrene, pyrene pentachlorophenol, after wet detention pond) phenanthrene, pyrene – Mobility, abundance, and treatability all Enteroviruses Enteroviruses Enteroviruses, some important bacteria and protozoa • Subsurface injection with minimal pretreatment Nickel , chromium, lead, (infiltration trench in parking lot or dry well) zinc Chloride Chloride Chloride – Abundance most critical 9
Basic Premise for Receiving Major Components of Water Assessments Receiving Water Assessments • No one single approach can be • Chemical (major impairments and uses) routinely used to accurately determine • Biological (community tolerance) or predict ecosystem health and • Physical/habitat (ecological integrity) beneficial use impairment. • Toxicity (availability of chemical • Each assessment approach or contaminants) component has associated strengths and weaknesses. The complexity of ecosystems require that these assessment tools be used in an integrated manner. The main objectives of most Reported State’s Bioassessment Tools monitoring studies may be divided • macroinvertebrate surveys (almost all programs, into two general categories: but with varying identification and sampling efforts) • habitat surveys (almost all programs) • Characterization (quantifying a few simple attributes of the parameter of interest ), • some simple water quality analyses and/or • some watershed characterizations • few fish surveys • comparisons (to standards or reference • limited sediment quality analyses conditions). • limited stream flow analyses • hardly any toxicity testing Other common objectives include identifying • hardly any comprehensive water quality analyses hot spots, examining trends, etc. 10
Experimental Design Issues • Budget • Basic Study Approach • Duration • Sampling Effort • Sampling Locations • Data Analyses • Quality Control/Quality Assurance 11
Basic Study Approach Parallel Stream Study (urban and Experimental designs can be organized in one rural stream) (Bellevue, WA) of the following basic patterns: Large Rain 1. Parallel watersheds (developed and urban Small Rain undeveloped) 2. Upstream and downstream of a city urban 3. Long-term trend rural Preferably, most elements of all of the above rural approaches can be combined in a staged approach Longitudinal Trend Study (above Long-Term Trend Study (Sweden) and below city) (San Jose, CA) 12
Likely Follow-up Testing Source Area Monitoring to Predict Sources of Runoff • Short-term chronic toxicity testing with additional species (lab and in situ ), Pollutants • Increased testing of toxicants, • Controlled washoff tests • Characterizing fish, plankton, periphyton, or mussel populations, • Small area sheetflow sampling • Measuring assimilative capacity via long • Large area sheetflow sampling term BOD and SOD testing, and/or • Outfall monitoring • Measuring productivity with light/dark bottle BOD in situ tests. 13
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Stormwater quality can vary greatly, even at a single site. Variations between events is greater than variations within events. WI DNR photo 15
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