Municipal Guide To Clean Water: Conducting Sanitary Surveys to Improve Coastal Water Quality
vegetation or unusual flow, odor, or color; turbidity; deposits/stains; floating debris; or damage to storm drainage structures (e.g., cracking, corrosion) can indicate grossly contaminated areas.17
based on the results. For example, if a monitoring station has high bacteria levels and the next station upriver is clean, continue to adjust the location of the upriver site to further narrow the problem area.
Fecal indicator bacteria monitoring
Preliminary screening for high bacteria scores should be conducted throughout the watershed to identify general pollution trends. Sample collection should be conducted using quality-assured protocols available via the MHB Program and/or state agencies such as the DEP and DMR.
Monitoring stations should be safely accessible. Obtain permission from property owners when appropriate. Use caution when collecting samples that you suspect may have high bacteria levels. Consider wearing gloves and wash your hands before and after sample collection.
After gathering generalized water quality data, specific streams, drainage pipes, etc. can be monitored to iden- tify pollution sources. Try to bracket (i.e., monitor above and below) potential pollution sources. For example, if a monitoring station located below a suspect property has recorded bacteria levels that are higher compared to an upriver location, this provides sufficient evidence to take a closer look. Additionally, a sample can be collected from any type of questionable flow, seepage, standing water, etc. within the survey area to determine bacteria levels.
Document monitoring locations via maps and/or
Monitoring should focus on human activities and distur- bance in the watershed. Depending on the size and char- acteristics of the watershed, start at the mouth of the river and/or storm drain on the shoreline and progressively move inland to bracket potential sources. Monitoring sites should be strategically placed to capture the impact of suspect areas such as properties with subsurface wastewater disposal (i.e., septic) systems in close proximity to the water body, agricul- tural operations, OBDs, POTW outfalls, CSOs, tributaries, etc.
Conduct bacteria monitoring during dry and wet weather. Trends in concentrations should be examined for “hotspots” within the drainage network and the monitoring locations should be adjusted
Similar to the challenge of determining how far inland the sanitary survey should extend, how far upriver a special monitoring study should extend depends on the characteristics of the watershed, recorded bacteria levels, and the resources available. In some cases, the monitor- ing data will continue to exhibit high bacteria levels as the stations move farther upstream. In other words, the sources of contamination may be extensive and there may not be a “clean” sample to determine the upper limit of the focus area. This is especially true in large watersheds, where the first tier of the special study and corresponding property survey may encompass the shoreline extending upstream to the head of tide region (i.e., the farthest point upstream where a river is affected by tidal fluctuations).
Testing for optical brighteners24
Optical brighteners are commonly used in commercial or retail products such as clothing detergents, dishwash- ing, personal care products, etc. to increase the white- ness of materials. After use, these products are typically flushed down the drain; therefore, the presence of optical brighteners in water likely indicates human sources of contamination (i.e., from an illicit discharge/straight pipe or graywater, or malfunctioning septic system).
Anchor absorbent pads via traps (i.e., metal cages) at sample locations. Retrieve after 48 hours and examine under a UV light to detect the presence/