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SECTION 4 water Quality Eualuatiou The other Clean Water Act program related to urban stormwater discharges is the total maximum daily load (TMDL) program. The Oregon Department of Environmental Quality (DEQ) has the responsibility for developing water quality standards that protect beneficial uses of rivers, streams, lakes, and estuaries. Once standards are established, the state monitors water quality and reviews available data and information to determine if these standards are being met and water is protected. Section 303(d) of the Federal Clean Water Act requires each state to develop a list of water bodies that do not meet the standards. The list serves as a guide for developing and implementing watershed pollution reduction plans to achieve water quality standards and protect beneficial uses. These watershed pollution reduction plans are referred to as TMDLs. With respect to the River Road Santa Clara basin, the tributaries in the basin eventually drain to the Willamette River, and the Willamette River has an established TMDL for bacteria, mercury, and temperature. The City and the County have both submitted and obtained DEQ approval on their TMDL implementation plans (see Section 2.6.2). This basin plan and the water quality management measures proposed in Section 4.3 were developed with these regulatory drivers in mind and will help the City and County move in the direction of reducing pollutant loads, improving water quality, and supporting compliance with these regulations. 4.1.2 Stormwater Discharges to the Subsurface (i.e., through drywells) As described in Section 2.5.4, a portion of stormwater runoff in the basin discharges to the subsurface through the use of drywells. Over the years, drywells have been a management strategy of choice for dealing with drainage in the River Road Santa Clara basin largely due to the flat topography, highly permeable soil conditions, and lack of a continuous storm drainage system. In the regulatory context, these drywells are referred to as Underground Injection Controls (UICs). Injection of water below ground, particularly to underground sources of drinking water, is strictly regulated under the Safe Drinking Water Act (SDWA). Injection systems fall into five classes (Class IN). Class V is reserved for small injection systems, including stormwater disposal systems such as drywells. As with the CWA, implementation of the SDWA has been delegated to the Oregon Department of Environmental Quality (DEQ). Infiltration has become increasingly more attractive as a management practice for addressing surface water quality concerns. Therefore, DEQ is concerned that stormwater disposal in underground systems will become more highly utilized. DEQ promulgated new state rules in 2001 to implement the SDWA. One of DEQ's intents in promulgating the new rules was to see that all stormwater management entities exercise the same care with respect to stormwater discharged to the ground that they do with stormwater discharged to surface waters under the NPDES permitting program. The 2001 rules require stormwater management entities to evaluate the quality of water disposed of in all facilities that have a "subsurface fluid distribution system ", including dry wells /sumps and infiltration trenches. The program also requires comprehensive stormwater management plans that address: 1) the need for and effectiveness of pre- treatment before injection; 2) spill prevention and control measures designed to minimize immediate harm to underlying aquifers; 3) systematic monitoring and record keeping; and, 4) system performance evaluation. DEQ representatives noted that there are long- standing regulations against groundwater contamination, and that the 2001 UIC program rules were designed to assist stormwater managers in complying with these regulations. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1an\FINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4 -2