2014-11-21_PERMIT FILE - C1996084 (23)

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• Ru(r =: Penrnts Flow, Crest, and Storm Events The Urri[ed Stales Geological Survey (LtSGSj has opera[ed nvo surface water gaging stations on [he general vicinity of the site: site 07L4060 at Stonewall. Colorado, on the Middle Fork of [he Purga[oire, and Site 071?4300 at Madrid. Colorado, on the Purga[oire mains[em. The Stonewall site is located approximately 13.3 miles upstream and drains 57.1 square miles. The ,Madrid site is located 8.6 miles downstream from Lorencito Canvon above the Trinidad Resen-oir and drains 50~ square miles. Numerous perennial, intermittent, and ephemeral streams drain into the Pureatoire between these nvo sires. The Stonewall station was monitored between 1978 and 1981, while flow at Ivladrid are available from 197? to present. During the period of record, flow at Stonewall ranged from 2.8 [o ~'_? cfs, while flow at Madrid ranged from 3.0 to 1640 cfs. The minimum monthly low tlow~ for the Madrid site is ~.8 cfs. and it occurred in February, 1977. The permit area is bounded on the east by the upper limits of the intermittent Lorencito Canyon wta[ershed, on the nonh b~ [he perennial Purga[oire River, and on the west by the perennial South Fork of the Purgatoire Ri~:ec. The tributaries draining into Lorencito from the mouth upstream consist of Little Jeff Canvon. Jett Canyon, Coyote Canyon, Puertecito Cam~on. Little Pine Canyon. Bonita Cam on. Chimney Canyon. Alamosa Canyon, Pancho Canyon. and Oso Canvon. These side tributaries are predominantly ephemeral. Lorencito. Cow Canyon and the South Fork of the Purgatoire are tributaries of the Purgatoire River. Flow data was collected from each of the moni[oring stations (~~fap 2.04.7-1) monthly during the 1996 baseline period. Flow were determined from measuremen[s of the depth of the water in the stream. These measurements were converted via stream discharge curves that were generated via the Manning's equation. During the months of January through July, flows are low' or non- existent at some stations. During the higher precipitation tnonths of July, August, and September, flows are higher. Precipitation da[a is presented in Section ?.04.08. Flows a[ [hese stations ranged from 0 CFS to 191 CFS (non-storm related). Station LC-4 had flows that were an pical of the other three stations. Flows at this station were higher in the spring than in the late summer/early fall. Flows at the CWC stations were extremely low with the station e.vhibitinJ no flow conditions over several months. Flows are summarized on Table 2.04.7-2. J r~Ea,r~r.,, ~,~:,o ~,r~: 3.04-_'7 (revised 6/;Q~97)