Construction Dewatering Discharges at Contaminated Sites
EPA has issued a new general NPDES permit, called the Remediation General Permit (RGP), for discharges of treated groundwater at contaminated sites. The RGP is available to construction site operators that need to dewater groundwater that has been contaminated with various pollutants including solvents and petroleum compounds.
EPA reissues Construction General Permit for New Hampshire.
The final CGP was issued on July 1, 2003 and now covers construction projects one acre and above or those that although smaller than one acre are part of a "common plan of development or sale" that totals an acre or more. The final CGP, the fact sheet, and the Federal Register Notice can be viewed and downloaded at the EPA Web site . A storm water pollution prevention plan (SWPPP) must be prepared and implemented for each project for which a Notice of Intent (NOI) application is filed.
EPA Encourages Electronic Filing of NOI’s for the Construction General Permit.
You need to insure that EPA receives and processes your complete NOI at least seven days before you plan to start land-disturbing work. EPA believes that due to mail delivery times and hard copy processing times that applicants can prevent up to a 30 day delay in project start-up if they File an Electronic NOI.
After you submit your NOI (electronically or by regular mail) to EPA, EPA will post your NOI on the NOI Search Page. You are authorized under the permit once your NOI is shown in "Active" status. NOIs listed as active have passed the seven-day "Waiting" period and are not "On Hold" due to eligibility concerns. If you do not use the internet for electronic filing and verifying the project status you must wait for the written acknowledgement from EPA before beginning construction. The telephone number for EPA's NOI Processing Center is (866)352-7755.
DES updates 305(b)/303(d) List of Impaired Waters and status of TMDLs.
To be eligible for coverage under the CGP applicants must incorporate measures and controls into their storm water pollution prevention plan (SWPPP) that are consistent with the assumptions and requirements (related to storm water) of any total maximum daily load (TMDL) on the receiving water that they plan to discharge to (see Part I.3.C.5.a. of the CGP). To determine if there is an approved TMDL for your receiving water and whether it requires any storm water controls see the DES TMDL Status List.
For the situation where there is an approved TMDL but there are no specific storm water controls the CGP (see Part I.3.C.5.b.) requires applicants to determine eligibility by consulting with DES. This section of the permit will apply in most cases in New Hampshire. DES has determined that applicants are eligible for the CGP (and further consultation is unnecessary) if they prepare a SWPPP that meets the requirements of the CGP and in preparing the SWPPP they select best management practices (BMPs) that optimize the removal of any pollutants causing impairment of the receiving water. To determine if the receiving water is impaired (i.e. on the 303d list) and which pollutants are causing the impairment follow these three steps:
- Determine if there are any river segments (lines) or lakes/impoundments (dots) colored red on the Map of 303d listed Waters. If no red appears in the town where your project is located then there are no impaired (303d listed) waters.
- or projects in towns where there are red lines or dots on the map used in item 1. above, determine the Assessment Unit (AU) numbers for the impaired waters by using the detailed Map of Assessment Units. Impairment does not necessarily mean 303d listed, proceed to step 3 below.
- For each water body in the town where your project is located that shows impairment for anything besides mercury (all waters are considered impaired due to mercury because of a statewide fish consumption advisory for mercury in fish tissue), confirm that the impairment is also 303d listed by looking for the water body Assessment Unit in the official New Hampshire Impaired Waters List. For each waterbody type (i.e., estuary, ocean, lake, impoundment and river), impaired waters are listed in numerical order by the numbers following the first 5 letters in the AU name.
- If you determine that you will discharge storm water from your construction site to 303d listed waters, you must select best management practices in your SWPPP that optimize the removal of any pollutants causing impairment of the receiving water. To evaluate which BMPs offer the best pollutant reductions for pollutants of concern you can search the International Storm Water Best Management Practices Database or view other guidance provided in this Web site.
Do I need to obtain the Construction General Permit if I want to create or expand an agricultural field?
No! The Clean Water Act in Section 402(l)(1) specifically exempts agricultural activities from Storm Water permitting. However, the activity must be conducted with proper timber harvesting best management practices to prevent erosion and off site migration of soil. Also, if at any time it is known that the activity will no longer be agricultural then the Construction General Permit must be obtained and followed.
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