Groundwater Susceptibility

The City of Kenmore Groundwater Susceptibility Map identifies the level of evaluation required at a particular site within the City. 1. Level One Hydrogeological Assessment – Areas of Moderate Susceptibility. a. A level one hydrogeologic assessment shall be required for any of the following nonresidential proposed activities at sites located within groundwater susceptibility zones that are rated as “moderate susceptibility”: (1) The storage, handling, treatment, use, production, recycling, or disposal of hazardous substances, other than hazardous household substances used according to the directions specified on the packaging for domestic applications. See RCW 70.105.010. (2) The use of injection wells, including on-site septic systems, except those domestic septic systems releasing less than 14,500 gallons of effluent per day and that are limited to a maximum density of one system per acre. (3) Any other activity determined by the city manager likely to have an adverse impact on groundwater quality or quantity, or on groundwater recharge. b. A level one hydrogeologic assessment shall include the following site and development-related information at a minimum: (1) Information regarding geologic and hydrogeologic characteristics of the site, including the permeability of the unsaturated zone (soils located above the groundwater table) based on existing data. (2) Groundwater depth, flow direction, and gradient based on available information. (3) Location of wells and springs within 1,300 feet of the project area. (4) Location of other critical areas, including surface waters, within 1,300 feet of the project site. (5) Available historic water quality data for the area to be affected by the proposed activity. (6) Best management practices (BMPs) proposed to be utilized. 2. Level Two Hydrogeologic Assessment – Areas of High Susceptibility. a. A level two hydrogeologic assessment shall be required for any of the following nonresidential proposed activities at sites located within groundwater susceptibility zones that are rated as “high susceptibility”: (1) The storage, handling, treatment, use, production, recycling, or disposal of hazardous substances, other than hazardous household substances used according to the directions specified on the packaging for domestic applications. See RCW 70.105.010. (2) The use of injection wells, including on-site septic systems, except those domestic septic systems releasing less than 14,500 gallons of effluent per day and that are limited to a maximum density of one system per acre. (3) Any other activity determined by the city manager likely to have an adverse impact on groundwater quality or quantity, or on groundwater recharge. b. A level two hydrogeologic assessment shall include the following site and proposal-related information at a minimum, in addition to the requirements for a level one hydrogeologic assessment: (1) Historic water quality and elevation data for the area to be affected by the proposed activity compiled for at least the previous five-year period, unless otherwise approved by the city manager. (2) Groundwater monitoring plan provisions. (3) Discussion of the effects of the proposed project on groundwater quality and quantity, including: (a) Predictive evaluation of groundwater withdrawal effects on nearby wells and surface water features. (b) Predictive evaluation of contaminant transport based on potential releases to groundwater. (4) Identification of the type and quantities of any hazardous materials that will be stored, handled, treated, used, produced, recycled, or disposed of on the site, including but not limited to materials such as elevator lift/hydraulic fluid, hazardous materials used during construction, materials used by the building occupants, proposed storage and manufacturing uses, etc. (5) Proposed methods of storing any of the above substances, including containment methods to be used during construction and/or use of the proposed facility. (6) Proposed plan for implementing protection standards during construction. (7) A spill prevention, control and countermeasure (SPCC) plan that identifies equipment and/or structures that could fail, resulting in an impact. Spill plans shall include provisions for regular inspection, repair, and replacement of structures and equipment that could fail. (8) A discussion of past environmental investigations, sampling, spills, or incidents that may have resulted in or contributed to contaminated soil or groundwater at the site. Attach copies of all historical and current reports, and sampling results.肯莫尔市地下水易感性地图（City of Kenmore Groundwater Susceptibility Map）明确了该市范围内特定场地所需开展的评估等级。 1. 一级水文地质评估——中等易感性区域 a. 针对位于评级为“中等易感性”的地下水易感性区域内的场地，开展以下任何一项非住宅拟建活动时，均需进行一级水文地质评估（hydrogeological assessment）： (1) 有害物质（hazardous substances）的储存、搬运、处理、使用、生产、回收或处置，但不包括按照包装说明用于家庭用途的危险家用化学品，详见RCW 70.105.010。 (2) 注入井（injection wells）的使用，包括现场化粪池系统（septic systems），但每日排放污水量低于14500加仑且最大密度限制为每英亩1套系统的家用化粪池系统除外。 (3) 由市经理认定的、可能对地下水水质、水量或地下水补给产生不利影响的任何其他活动。 b. 一级水文地质评估至少应包含以下与场地及开发相关的信息： (1) 场地的地质与水文地质特征相关信息，包括基于现有数据得出的非饱和带（unsaturated zone，即地下水位（groundwater table）以上的土壤）的渗透性。 (2) 基于现有资料得出的地下水埋深、流向及水力梯度。 (3) 项目区域1300英尺范围内的水井与泉眼位置。 (4) 项目场地1300英尺范围内的其他关键区域（包括地表水）位置。 (5) 拟建活动影响区域的现有历史水质数据。 (6) 拟采用的最佳管理实践（Best Management Practices, BMPs）。 2. 二级水文地质评估——高易感性区域 a. 针对位于评级为“高易感性”的地下水易感性区域内的场地，开展以下任何一项非住宅拟建活动时，均需进行二级水文地质评估： (1) 有害物质的储存、搬运、处理、使用、生产、回收或处置，但不包括按照包装说明用于家庭用途的危险家用化学品，详见RCW 70.105.010。 (2) 注入井的使用，包括现场化粪池系统，但每日排放污水量低于14500加仑且最大密度限制为每英亩1套系统的家用化粪池系统除外。 (3) 由市经理认定的、可能对地下水水质、水量或地下水补给产生不利影响的任何其他活动。 b. 除一级水文地质评估的要求外，二级水文地质评估至少还应包含以下与场地及拟建方案相关的信息： (1) 拟建活动影响区域的历史水质与高程数据，数据采集周期至少为过去五年，经市经理批准的情况除外。 (2) 地下水监测方案条款。 (3) 拟建项目对地下水水质与水量的影响分析，包括： (a) 地下水取水对周边水井及地表水水体影响的预测评估。 (b) 基于潜在地下水污染物释放的污染物运移预测评估。 (4) 明确将在场地内储存、搬运、处理、使用、生产、回收或处置的任何危险物料的类型与数量，包括但不限于电梯液压油、施工期间使用的危险物料、建筑使用者使用的物料、拟议的储存与生产用途物料等。 (5) 上述各类物料的拟储存方式，包括施工期间及/或拟建设施运营期间拟采用的防渗措施。 (6) 施工期间拟实施的保护标准实施方案。 (7) 溢油预防、控制与应对计划（Spill Prevention, Control and Countermeasure, SPCC），该计划需明确可能失效并造成影响的设备和/或建构筑物。溢油计划应包含对可能失效的建构筑物与设备进行定期检查、维修与更换的条款。 (8) 对可能已造成或加剧场地土壤或地下水污染的既往环境调查、采样、溢油事件或其他事故的分析说明，并附上所有历史与当前报告及采样结果的副本。