Grape Creek

About

Grape Creek and the Penrose (Pleasant Valley) Water System. Grape Creek drops out of the Sawatch Range in south-central Colorado and runs north through Chaffee and Custer counties to meet the Arkansas River. For most of its length the creek is a thin, cold, high-country stream, but the stretch below Deweese Reservoir is something else entirely: a dam-controlled tailwater with a flow that swings hard between irrigation releases (Source: Colorado DWR CDSS API — surfacewater/surfacewaterstations, division 2, station GRABDWCO; Colorado DWR CDSS API — structures, waterSource=GRAPE CREEK, division 2). The gauge that reads it, DWR station GRABDWCO, sits at river mile 27.75 about five miles above the confluence, and its daily averages over the 30 days to 2026-10-27 ranged from 4.89 to 164 cfs around a median of just 15.8 (Source: Colorado DWR CDSS API — surfacewater/surfacewatertsday, abbrev GRABDWCO, min-measDate 2026-09-28, max-measDate 2026-10-28). Deweese and the Penrose (Pleasant Valley) system are what put that water there: the reservoir and its exchange reaches are operated as one unit, releasing irrigation water to the Arkansas downstream while taking the Arkansas's water up the Platte for the valley's benefit (Source: Colorado DWR CDSS API — structures, waterSource=GRAPE CREEK, division 2). Below the dam the creek is a trout stream rather than a paddling one — a low-gradient tailwater with a bed of gravel and cobble that greens up when the releases come on (Source: Colorado DWR CDSS API — surfacewater/surfacewaterstations, division 2, station GRABDWCO). The Upper Arkansas Water Conservancy District is the listed data source for the station, and the Southeast Colorado Water Conservancy District is a partner on the Deweese exchange reaches (Source: Colorado DWR CDSS API — surfacewater/surfacewaterstations, division 2, station GRABDWCO, dataSource UAWCD; Colorado DWR CDSS API — structures, waterSource=GRAPE CREEK, division 2, associatedContacts). Grape Creek has no USGS gauge: the station's usgsSiteId is the DWR-internal code 20C, which the USGS site service rejects outright (Source: USGS Water Services site query, sites=20C, HTTP 400 'Site number length must be no less than 8 numeric digits').