Thurston Critical Aquifer Recharge Areas USDA DNR

Critical aquifer recharge areas are those areas that provide a critical recharging effect on aquifers used for drinking water, including areas that are vulnerable to contamination or reduced recharge. CARAs are divided into three categories depending on sensitivity: Category I - extreme aquifer sensitivity; Category II - high aquifer sensitivity; Category III - moderate aquifer sensitivity. See Thurston County Code Chapter 24.10.010 for full definitions. This data set combines soil-based CARAs with geology-based CARAs. Geology-based CARA categories were developed in conjunction with Nadine Romero, Thurston County's hydrogeologist, using available data from the Washington State Department of Natural Resources. Where an area has conflicting CARA categories between soils and geology, the more restrictive category prevails. Geology mapping at the 1:24,000 scale was only available for some portions of the county at the time of CAO update, the rest is mapped at 1:100,000 scale. Therefore it is important to not to accidentally use the data at a scale beyond its native resolution. The geology data are organized by quads. The 24k quads are: Shelton, Squaxin Island, Longbranch, Summit Lake, Tumwater, Lacey, Nisqually, Maytown, and East Olympia. The 100k quads are: Kamilche Valley, Capitol Peak, Little Rock, Tenalquot Prairie, McKenna, Harts Lake, Oakville, Rochester, Violet Prairie, Bucoda, Vail, Lake Lawrence, Bald Hills, Eatonville, and Elbe. This data was created by the Thurston County Hydrogeologist and Long Range Planning staff in 2014-2015 using USDA NRCS Soils data and Department of Natural Resources Geologic Data.

关键含水层补给区（Critical Aquifer Recharge Areas）指对用作饮用水源的含水层发挥关键补给作用的区域，涵盖易受污染或补给量缩减的区域。CARAs按敏感性划分为三类：I类——极端含水层敏感性；II类——高含水层敏感性；III类——中等含水层敏感性。完整定义详见瑟斯顿县法典第24.10.010章。
本数据集整合了基于土壤的CARAs与基于地质的CARAs。基于地质的CARAs分类由瑟斯顿县水文地质学家纳丁·罗梅罗（Nadine Romero）联合华盛顿州自然资源部的可用数据共同制定。当某区域的土壤类与地质类CARAs分类存在冲突时，采用限制性更强的分类标准。
在本次CARAs数据更新时，该县仅部分区域可获取1:24000比例尺的地质测绘数据，其余区域的地质测绘比例尺为1:100000。因此，切勿超出数据原生分辨率的比例尺使用本数据集。
地质数据按图幅（quads）组织：1:24000比例尺图幅包括谢尔顿、斯夸申岛、朗布拉奇、萨米特湖、塔姆沃特、莱西、尼斯夸利、梅敦和东奥林匹亚；1:100000比例尺图幅包括卡米尔奇谷、国会峰、小石、特纳尔夸特草原、麦肯纳、哈茨湖、奥克维尔、罗切斯特、维奥莱特草原、布科达、韦尔、劳伦斯湖、鲍尔希尔斯、伊顿维尔和埃尔贝。
本数据集由瑟斯顿县水文地质学家与长远规划部门职员于2014-2015年，依托美国农业部自然资源保护服务局（USDA NRCS）土壤数据与华盛顿州自然资源部地质数据编制完成。