Monitoring Activities

Biological Monitoring: In October 2010, BDCWA and Aquatics Associates will be conducting biological monitoring on Big Dry Creek.

Instream Water Quality/Flow: City and County staff conduct instream monitoring on a monthly basis. (Click here for a quick summary)

Streamflow: BDCWA helps fund operation of the USGS stream gauge behind Front Range Community College.

Monitoring Program Overview

The Big Dry Creek monitoring program focuses on the main stem of Big Dry Creek and includes water chemistry, flow, habitat, fish, and benthic macroinvertebrate sampling. Ten locations beginning below Standley Lake and spanning to Weld County near Fort Lupton are monitored by city staff on a monthly basis. The water quality monitoring program is an ambient-based, voluntary program that includes grab samples collected at seven instream locations and three municipal wastewater discharges. (Municipal wastewater discharges are also monitored by municipal permittees in accordance with their Colorado Discharge Permit System [CDPS] permits.)

Water quality monitoring is conducted in accordance with a Sampling and Analysis Plan, which is periodically reviewed and updated. Data collected under this monitoring program are entered into a master database following QA/QC by the steering committee. This database is currently in Microsoft Access in a STORET-compatible format. On an annual basis, the water quality data are retrieved from the database and compared to Colorado Water Quality Control Commission stream standards to assess whether the stream is attaining stream standards. Trends regarding water quality and flow are identified and discussed in an annual technical memorandum presented at a Watershed Association meeting and are subsequently summarized in a Watershed Association newsletter. Additionally, data are periodically provided to the Colorado Water Quality Control Division for various purposes such as 303(d) list development, Regulation 38 Rulemaking Hearings, and development of preliminary effluent limits for municipal wastewater discharges in the watershed.

The aquatic monitoring program began in 1997 to document the abundance and distribution of fish and benthic macroinvertebrate populations and to describe the physical habitat at select locations in Big Dry Creek. The program has evolved over time and is currently conducted on a biannual basis in the fall during low-flow conditions. Biological monitoring locations include a targeted subset of the water quality monitoring locations. For a description of the biological monitoring program, see the 2010 Biological Monitoring Report.

Special supplemental sampling programs are also periodically conducted by the Watershed Association and the cities. Representative examples include E. coli, selenium and temperature.

Other entities also conduct independent monitoring in the watershed. For example, the U.S. Department of Energy monitors discharges from the Rocky Flats property, the Standley Lake Cities monitor Standley Lake, and the City and County of Broomfield monitors Great Western Reservoir and Walnut Creek. The U.S. Geological Survey also owns and operates two gauges in the watershed, with data available online.