TMDL Watersheds

This dataset depicts TMDL watershed boundaries. A TMDL watershed is the area covered by a TMDL equation. It consists of one or more impaired streams that have an assigned Cause Group Code (CGC). The CGC is the link between the TMDL and the Assessment Report. The TMDL equations are stored in a table in the TMDL database. Currently, the database contains about 650 equations, which are set across the entire state. Each equation includes the Waste Load Allocation (WLA), which is the portion of the TMDL that accounts for pollution from point sources (permits). The WLA cannot be exceeded during permit reissuance or its TMDL equation must be modified. Click Here to view Data Fact Sheet.本数据集呈现了总最大日负荷量（Total Maximum Daily Load，TMDL）流域的边界。TMDL流域指由TMDL公式覆盖的地理区域，其包含一条或多条已分配原因组代码（Cause Group Code，CGC）的受损溪流。CGC是连接TMDL与评估报告的关键纽带。TMDL公式存储于TMDL数据库的数据表中，目前该数据库共收录约650条分布于全州的公式。每条公式均包含污染负荷分配量（Waste Load Allocation，WLA）——即TMDL中核算点源（排污许可）污染贡献的部分。在排污许可续期环节，不得超出该WLA限值，否则需对其对应的TMDL公式进行修改。点击此处可查看数据资料单（Data Fact Sheet）。