The proposed revision adopts minimum flow rules for the tidal reaches of the lower Peace River. 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) of 130 cubic feet per second (cfs) has also been proposed. A LFT is defined to be the flow that serves to prohibit withdrawals under very low flow conditions throughout the year. The lower Peace River minimum flow was determined based on the sum of the combined flows of the Peace River at Arcadia, Horse Creek and Joshua Creek. For the low flow period (Block 1, which runs from April 20 through June 25), it was determined that more than 15 percent of the historically available habitat would be lost, if flows were reduced by more than 16 percent based on the combine flows of the three gages noted above as long as total daily withdrawals from Peace River were limited to 400 cfs. For the medium flow period (which runs from October 27 of one year through April 19 of the next), it was determined that more than 15 percent of historically available habitat would be lost if flows were reduced by more than 16 percent at or below a flow of 625 cfs based on the combined flows of three gages, but that when flows exceeded 625 cfs, up to 29 percent of the combined flows could be taken without causing significant harm to the available habitat as long as total daily withdrawals from off the Peace River were limited to 400 cfs. For the high flow season of the year (which runs from June 26 through October 26), it was determined that more than 15 percent of historically available habitat would be lost if flows were reduced by more than 16 percent at or below a flow of 625 cfs based on the combined flows of the three gages, but that when flows exceeded 625 cfs, up to 38 percent of the combined flows could be taken without causing significant harm to the available habitat as long as total daily withdrawals from off the Peace River were limited to 400 cfs.