Summary


For purposes of the rule, the Anclote River system includes the watercourse from the headwaters to the Gulf of Mexico. For this rule, the location of the gage represents the division between the freshwater portion of the river upstream of the gage and the estuarine portion downstream of the gage. Significant harm was defined as occurring when modeled withdrawals from the baseline or unaltered flow conditions caused more than a 15 percent decline in any one of several ecologically based habitat metrics. In addition to determination of an allowable percent flow reduction, a low flow threshold (LFT) has also been proposed for the freshwater segment. A LFT is defined to be the flow that serves to prohibit withdrawals under very low flow conditions throughout the year. Three seasons (Blocks 1, 2 and 3) were evaluated separately and a freshwater and estuarine MFL was determined for each Block. The proposed freshwater minimum flows allow reduction of up to 11% of Block 1 (April 12 through July 21) baseline flows, up to 18% of Block 3 flows (October 15 through April 11) and up to 14 % of Block 2 flows (July 22 through October 14) when flows are between 12 cfs and 138 cfs. A freshwater LFT is established so that withdrawals are prohibited from depressing flows below 12 cfs at any time. When baseline flows exceed 138 cfs, up to 8% of the excess flows may be withdrawn. Estuarine MFLs are similar, but do not have a low flow threshold. Proposed minimum flows allow reductions of up to 12% of Block 1 flows, up to 16 % of Block 2 flows and up to 18%, of Block 3 flows.