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Stormwater Monitoring Program |
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Stormwater Monitoring Program |
The Stormwater Quality Program, Water Quality and Environmental Services, City of Boulder, conducts water quality monitoring to assess the impacts of point and non-point sources of pollutants to Boulder Creek and to help develop mitigation measures to reduce these impacts. To understand the threats which Boulder’s surface waters are facing, it is necessary to examine how the resources are changing over time. Accurate information on the status and trends of the environment can help identify source controls. The Stormwater Quality Program collects monthly water quality samples from the North Boulder Creek Falls to the confluence of Boulder Creek with Coal Creek.
TOC bottles are obtained from the USGS, where the bottles are washed with hot soapy water, rinsed with tap and distilled water, and burned for 8 hours at 250 degrees C. The remaining bottles are cleaned in a dishwasher at the waste water laboratory. The dishwasher provides a hot water and detergent wash, steam cycle, and a deionized water rinse. Bottles used for metals are also soaked in 3% nitric acid (HNO3) and then rinsed with deionized water three times. Bottles are then air-dried.
In the field, sample bottles are rinsed two times with water being collected, unless a preservative or dechlorinating agent has been added to bottle prior to use. Various types of sample bottles are used depending on constituent being tested for and method of analysis being used.
Samples are taken from mid-channel or the area in the channel which best represents the flow. Sample bottles are submerged to approximately 60% of the water depth and water is allowed to flow into them. The sample is capped and shaken. One to two inches of space is left in the bottle to allow for thermal expansion (unless sample analysis requires that no air space be left).
Sample preservative is added after sample collection as prescribed by each analytical method. Metals samples are filtered in the laboratory before being acidified.
Sample labels are completed and samples are placed in cooler with blue ice. Samples are transported to laboratory and placed in refrigerator for storage at 4 ° C.
Field blanks are used for every sampling event. Field blanks are filled with deionized water and are treated in the same manner as other sample bottles. Duplicate samples are also collected for each sampling event.
The Orion Model 130 conductivity meter is used for Specific Conductance (SC) and water temperature. The probe is calibrated before each sample event with a potassium chloride (KCl) solution of 1412 micromhos/cm at 25° C.
The Orion Model 840 DO meter and the Orion Model 140 conductivity meter are used as backups if a problem with the main meters occurs in the field.
Flow velocity is measured using the Marsh-McBirney Flo-Mate 2000 portable flowmeter. USGS midsection methods, as described in the Water Measurement Manual, are followed. Calibration is performed at the factory.