City updating erosion control criteria for construction sites

Engineers say the most dangerous time for creeks, caves and other critical environmental features is when there is construction nearby, increasing the possibility of erosion and sedimentation from poor or nonexistent pollution control barriers.

 

With that in mind, staffers in the Watershed Protection and Development Review department are in the first phase of drafting revisions to the city’s environmental criteria manual dealing with erosion and sedimentation controls during construction. The rewrite was ordered last year as part of the Council’s decision to adopt new rules governing redevelopment in the Barton Springs Zone of the Edwards Aquifer (See In Fact Daily, November 9, 2007).

 

“The current criteria had not been comprehensively updated in 10 years,” Mike Kelly with WPDR told the Environmental Board this week. “The current criteria lacks concise, science based-requirements to that are going to be effective of achieving the goals of…minimizing, to the greatest extent possible, on-site erosion and its off-site damages.”

 

The staff has identified eight areas for improving the city’s regulations designed to prevent erosion at construction sites. Those include bringing the paperwork developers are required to file with the city more in line with state and federal forms, changing inspection and fiscal surety requirements, and thoroughly reviewing the “best management practices” used by other cities.

 

The science behind erosion control, Kelly said, has advanced significantly since the mid 1990’s, based partly on real-world experience of some of those techniques considered to be BMPs. “It’s difficult to really track down the source of some of these recommendations when you really get into it,” Kelly said. “It seems as if we’re all copying each other and saying ‘this is the best management practice’. That doesn’t make me feel great as an engineer.”

 

In addition to using current science, the staff is proposing step up inspection requirements for erosion control measures at construction sites. While the City does not have the resources to significantly boost its inspection staff, Kelly said, they are considering new regulations to require developers to hire their own certified inspector for regular checkups, which would be supplemented by the city inspectors.

 

The city is also considering requiring a specialized certification for inspectors, which would apply to both city employees and those in the private sector. Currently, erosion control plans can be designed and inspected by a registered professional engineer. “The consensus in the industry from experience with our own review process…as well as literature…is that engineers were kind of handed this,” Kelly said. “There was not another body of professionals that seemed to be a good fit and had some sort of legitimicacy, in the form of licensing, to take this on. However our education does not really include any formal training in this. The emerging opinion in the industry is that specialized certification for this is going to make a big difference in how controls are designed, installed, inspected and maintained.” The International Erosion Control Association has established standards for that type of certification (http://www.cpesc.org/).

 

The staff’s suggestions also include requiring the soil stabilization during construction and increasing the design requirements for temporary erosion controls so that they can handle a 10-year rated storm event. Currently, those controls are required to be able to handle a two-year storm.

 

The suggestions were drawn up after consultation with industry and stakeholder groups, including the Save Our Springs Alliance, Sierra Club, the Association of General Contractors, and private engineering firms. “Because of the sweeping scope of our updates, we wanted to get as much community input as possible,” Kelly said. “We’re in round one of public input. There will be an even more formal round to refine these suggestions.” That process is expected to take several months. Staffers hope to have the revisions to the criteria manual, which do not require a vote by the Council, finished by the end of the year.

 

A representative from SOS was at Wednesday’s Environmental Board meeting to offer additional suggestions. “Now that we have the redevelopment ordinance in the Barton Springs Zone, we need specific requirements on those construction sites where they’re tearing up old dirty parking lots and leaving piles of materials sitting,” said Sarah Baker with SOS.

 

Environmental Board Members also had suggestions and questions for the staff about the project. One area of particular interest with the proposal to have developers or construction companies hire their own certified inspectors. “What we have to be careful about is getting into a situation where the city is inspecting less, or for lack of a better term, letting the fox watch the henhouse,” said Chair Dave Anderson.

 

The Environmental Board does have a subcommittee to deal with the rewrite of the criteria manual, which could meet again as the staff solicits more public input.