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Regional WELLHEAD PROTECTION Process Status. by Lloyd Brewer Environmental Programs City of Spokane . Why?. Protection of: Drinking water quality Infrastructure investments Hydro-geological resources Local economy From: Increased cost of water Health Risks (Acute & Chronic).
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Regional WELLHEAD PROTECTION Process Status • by Lloyd Brewer Environmental Programs City of Spokane
Why? • Protection of: • Drinking water quality • Infrastructure investments • Hydro-geological resources • Local economy • From: • Increased cost of water • Health Risks (Acute & Chronic)
compound Contaminant Types & 2007-2008 Incidents (CDC) • Chemical (1) • Degradable • Non-degradable • Radiological • Biological • Bacteria (21) • Viruses (5) • Parasites (3) • 4,128 illnesses (4 unknown cause), 3 deaths
Chronic Risk • Critical Materials 2,241 on City List • Examples: • Hexavalent Chromium MCL 100 ppb; CAHG 0.02 ppb • Arsenic MCL 10 ppb; MCLG 0 • Lead Action Level 15 ppb; MCLG 0 • Trihalomethanes MCL 80 ppb; MCLG 0
Stormwater Facilities & Distance from Wells • Additional protection of groundwater quality can be achieved by: • Siting BMP’s outside of capture areas, or • Careful siting and maintenance inside capture areas • Should be sited as far up-gradient of wells as possible • The greater the separation distance, the more benefit is achieved • Increased warning time • Increased attenuation of degradable pollutants • Somewhat increased dilution of non-degradable pollutants
Main Considerations • The main considerations for siteing recharge facilities are (1) whether the separation distance can be increased to allow for greater attenuation of some pollutants during routine stormwater infiltration events, and (2) whether the recharge facility will alter the alignment of downgradient or cross-gradient SWPAs.
Other Considerations A 10-year (or less frequent) precipitation event will generate such large quantities of stormwater that chloride and other pollutants would likely be much more diluted than those seen during more routine conditions. Adverse conditions such as flooding do not result in the collection of samples that are representative of typical stormwater quality. The highest concentrations of pollutants in stormwater typically occur during the first 30 minutes of the first rainfall event that occurs after an extended dry period (see pgs. 24 & 25 of EPA, 1992).
History • a) 1979 – Spokane Aquifer Water Quality Management Plan • b) 1986 – Safe Drinking Water Act amended to require States to develop Wellhead Protection Plans • c) 1992-1993 – grant for technical aquifer model development • d)1998 (OPR 98-144) agreement between the SAJB, Spokane County, Millwood, and the City of Spokane for WHPPC • e) Sept. 2007 SAJB Wellhead Protection Update • f) Nov. 2007 – Council Resolution 2007-0125 Stated support for regional wellhead protection • g) 2011 State DOH grant for Wellhead Protection Aquifer Model update • h) Now - WHPPCC works to complete recommendations
SAJB Wellhead Protection Update Issues • Aquifer / Aquifer Water Quality Recognition/Protection • Special Wellhead Protection Area (SWPA) recognition by land use regulators • Stormwater handling in/or impacting SWPAs • Wastewater handling in SWPAs • Septic systems in/or impacting SWPAs • Reclaimed water use in/or impacting SWPAs • Control of relatively high risk business activities in SWPAs
SAJB Wellhead Protection Proposed Mechanisms (slide 1 of 2) • Promote consistent regional aquifer protection • Special Wellhead Protection Area (SWPA) recognition by land use regulators ( one year time of travel ) • Improve communication between land use regulators and drinking water purveyors • Increase control of reclaimed water, stormwater, wastewater, & septage handling in SWPAs • Checks on NEW stormwater & reclaimed water facility proposals to assess potential to adversely impact SWPAs/wells
SAJB Wellhead Protection Proposed Mechanisms (slide 2 of 2) • Stormwater- reduce contaminant concentrations reaching the aquifer using source control, increased dispersion/degradation, and treatment systems beyond the minimum normally required. • Where pathogenic organisms are potential contaminants such as in surface water, seek a distance of 1 year time of travel from source to well. • For relatively high risk business activities who do not have approval of the water purveyors and land use regulator whose areas they would develop in – a requirement to get a conditional use permit via public process.
Proposed Relatively Risky Business Activities List (slide 1 of 3 ) • Animal Feedlots • Bio-research Facilities • Chemical/Agricultural chemical warehousing • Composite (“fiberglass”) Products Manufacturing • Dry Cleaning (performed on location) • Electronics Manufacturing • Electroplating/Metal Finishing • Engine & Vehicle Repair/Service/Salvage • Furniture Stripping • Junk Yards
Proposed Relatively Risky Business Activities List (slide 2 of 3 ) • Metal Fabrication • Mining/Sand & Gravel Extraction • Storage of Critical Materials • Transfer of Critical Materials • Oil & Gas Drilling • Paint Manufacturing and Wholesale Storage • Petroleum Bulk Storage & Transmission • Photo Processing • Printing and Lithography • Solid Waste Handling & Recycling Facilities
Proposed Relatively Risky Business Activities List (slide 3 of 3 ) • Vehicle Washing • Wastewater Bulk Storage, Treatment & Pumping Facilities • Wood Treatment Facilities
NEXT STEPS • Complete WPPCC Recommendations • Pass recommendations & process details to the SAJB, other purveyors, and WA-DOH • Pass recommendations to local government planners, plan commissions, and elected officials • Support local government processes to put recommendations into place • There will be opportunities for further public input at the local government venues
Questions? Follow the process at: www.greenspokane.org/water/ or www.sajb.org
Draft Recommendations Within SWPAs slide 1 of 3 5) The Wellhead Protection PCC recommends that each jurisdiction adopt the following in their Critical Area Ordinances Disposal of Stormwater within Special Wellhead Protection Areas • a) Will be in compliance with the Spokane Regional Stormwater Manual and/or the Stormwater Management Manual for Eastern Washington and no new direct injection of untreated stormwater1 in special wellhead protection zones is allowed. 1 untreated stormwater here means stormwater that has not passed through a stormwater best management practices facility before discharge to a drywell regardless of the level of treatment provided.
Draft Recommendations Within SWPAs slide 2 of 3 • b) The size of the post-development basin flowing into a special wellhead protection zone shall not be greater than the size of the predevelopment basin flowing into it unless an engineering analysis demonstrates that the proposed basin increase does not have an adverse impact to the wellhead protection zone. • c) In special wellhead protection areas stormwater injection and injection wells should be located as far as practical from wellheads. • d) Except for uncontaminated roof runoff, no stormwater discharge treated or otherwise should occur within100 feet of a drinking water well.
Draft Recommendations Outside of SWPAs • d)Stormwater disposal facilities over the Aquifer but not in special wellhead protection zones which are: a. designed to handle greater volumes than would be modeled coming from a wellhead protection area, or, b. immediately up-gradient of a wellhead protection zone and within 2 year time of travel, or c. near the aquifer boundary, or d. facilities that would be handling runoff which at least in part came from perennial surface water bodies, • should be required to be modeled using the same aquifer model used for the delineations
Acceptable When • 1) no more than 20% of any well’s modeled production comes from this sourceof recharge, and • 2) where stormwater runoff could include perennial surface water, the annual recharge is at least a oneyear time of travel from all drinking water wells.
Draft Recommendations Within SWPAs slide 3 of 3 • e) Stormwater facilities within 300 feet of a drinking water well need to provide treatment at least equivalent to a 208 swale with engineered soil. • f) Stormwater facilities within special wellhead protection areas should be designed such that: 1) the impervious surface area they each handle is less than the standard area of such facilities; and/or 2) treatment systems beyond the minimum are added; and/or 3) such stormwaterfacilities should be maintained and rehabilitated at a frequency exceeding the norm. • g)At the well, maximum well pumping should result in no greater than a 20% stormwater contribution given annual average stormwater injection.
Storm Events & Distance from Wells • However, pollutant transport models and in-aquifer dilution calculations illustrate that a small versus large separation distance will have little, if any, effect on pollutant attenuation during low-recurrence high-rainfall events (such as the 24-hour event that has a 10-year or greater recurrence interval), particularly for a non-degradable pollutant such as chloride that may be present in municipal stormwater generated during such an event (for example, a rain on-snow event that generates stormwater from roadways that have been salted during the winter, prior to the event).1
Balance Needed • Cost of protection vs impact of loss • Stormwater & Wastewater costs are already increasing • Existing regulation vs new regulation
Generally one of two solutions • Clean up contaminated water • OR • Abandon the well