The Big Dry Creek watershed originates in unincorporated
Jefferson County at the mouth of Coal Creek Canyon at an elevation of
approximately 6,000 feet above mean sea level. The watershed drains
easterly from the headwaters area across Rocky Flats, where several
tributaries form including Walnut Creek, Woman Creek and Upper Big Dry
Creek. The flow in Big Dry Creek is heavily regulated by releases from
Standley Lake reservoir. Below Standley Lake, Big Dry Creek flows in a
northeasterly direction to its confluence with the South Platte River near
Fort Lupton in Weld County. Significant portions of the watershed are
currently undergoing rapid urban development, transitioning from
predominantly agricultural uses to include a mixture of residential,
commercial and industrial uses. The total drainage area at the confluence
is approximately 110 square miles with a 42-mile length. The map below
illustrates the watershed boundaries.