Delaware

Delaware Department of Natural Resources and Environmental Control
Division of Water-Surface Water Discharges
89 Kings Highway
Dover, DE 19901

Stormwater permit is incorporated into regulations--administrative extension began a year and a half ago, currently revising the regulations and anticipate they will be effective in a few years.

Storm Water Discharges Associated With Industrial Activity To Be Covered Under the NPDES General Permit

Section 9.1 of the Regulations Governing the Control of Water Pollution (General Permit Program)

9.1.4.2 Sampling Procedures and Conditions - Storm water must be sampled according to the instructions below.

9.1.4.2.1 Sample Type

9.1.4.2.1.1 A grab sample shall be collected from a storm water discharge resulting from a storm event that is greater than 0.1 inches of magnitude and that occurs at least 72 hours from the previously measured (greater than 0.1 inch rainfall) storm event. The required 72 hour interval is waived where a preceding measurable storm event did not result in a measurable discharge from the facility. The grab sample shall be taken within the first thirty (30) minutes of a storm water discharge. If it is not practicable to take the sample during the first 30 minutes, sample during the first hour of discharge and indicate why a grab sample during the first 30 minutes was impracticable. The permittee shall also allow for two (2) full days of standard operating activities at the facility since the last rainfall event that resulted in runoff from the facility.

Magnitude: greater than 0.1 inches

Interval Between Storms: at least 72 hours from the previous 0.1 inch storm

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