Shoreline soil erosion. (Credit: Public Domain)
On construction sites, project managers sometimes don’t see the value in best management practices that can reduce soil erosion. But that is an important consideration, especially in states like California that have regulations that attempt to prevent the loss of soil. If managers disregard them, they can face hefty fines or work stoppages.
Scott Thorne, president of Scott Thorne Environmental Consulting Inc., knows this firsthand, as many of his projects deal with construction-site inspections for water quality. On the job, he and his staff commonly monitor during rain events where there are discharges, keeping tabs on turbidity which is a good indicator of soil loss.
“Discharges, depending on the construction site, will be where future storm drain connections will be or may already exist. Sometimes if the site has unimproved areas, we might sample water as it leaves the site in natural swales or ditches,” said Thorne. “Occasionally there may be a non-stormwater discharge that we might have to sample but they are fairly infrequent.”
At these spots, Thorne and crew use a Hach 2100Q Portable Turbidity Meter. By checking the cloudiness of the water, they attempt to measure the amount of sediment leaving. This typically correlates to the type and overall function of erosion control practices on site.
In addition, they also sometimes measure pH along with turbidity. That’s important if some sort of concrete work, or another type of soil amendment, has recently been completed.
“Data collected is kept on our inspection records and uploaded to the state’s web-based tracking program. Data within parameters has to be uploaded by end of reporting year. Data indicating exceedances is uploaded after storm events,” said Thorne. “Data also helps us to justify cost associated with installation of soil loss controls on a construction site. Many owners do not feel cost associated with stormwater plans is justified and data helps us to physically prove money spent is money saved in terms of violations or stopped work.”
In the most recent construction season, Thorne says that most of the data came in as expected. But there are some key things they’ve revealed over the years about the loss of soil around construction projects in California specifically.
“The amount of source-control best management practices directly affect the soil loss. Our results and sampling sessions are really related to how wet our winters are,” said Thorne. “Our state has been experiencing abnormally dry conditions the last four years or so.”
Top image: Shoreline soil erosion. (Credit: Public Domain)