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Division of Watershed Stewardship

Statutory Authority: 7 Delaware Code, Section 4006(h) and (i) (7 Del.C. §4006(h) & (i))
7 DE Admin. Code 5101



Regulatory Guidance Memorandum RGM-1 Supporting Regulation 5101 Sediment and Stormwater Regulations

The Department of Natural Resources and Environmental Control (DNREC) Division of Watershed Stewardship Sediment and Stormwater Program has released a regulatory guidance document titled “Regulatory Guidance Memorandum RGM-1” for public review. This document supports Regulation No. 5101 Sediment and Stormwater Regulations, as set forth at 7 Del.C. §4006(h) and (i).

A synopsis of RGM-1 is as follows: The Delaware State Office of the Natural Resources Conservation Service (NRCS) has adopted the current National Oceanic & Atmospheric Administration (NOAA) Rainfall Distribution curves for the hydrologic design of conservation practices in Delaware in place of the NRCS Type II Rainfall Distribution Curves. In keeping with this, the Delaware Sediment & Stormwater Program will begin accepting the use of the NOAA Rainfall Distribution Curves for the hydrologic design of stormwater management practices intended to comply with the Delaware Sediment & Stormwater Regulations effective January 1, 2020. NOAA Curve C should be used in New Castle and Kent Counties. NOAA Curve D should be used for Sussex County.

The DNREC Sediment and Stormwater Program hereby provides notice of this regulatory guidance document, pursuant to 7 Del.C. §4006(i), which incorporates the provisions of 7 Del.C. §6004. A public hearing will NOT be held unless the Secretary receives a meritorious request for a hearing within 15 days of date of this notice, ending December 15, 2019. A request for a public hearing shall be in writing and show familiarity with the regulatory guidance document and provide a reasoned statement of the regulatory guidance document’s probable impact.

This document may be reviewed at the following link:

For appointments to review the regulatory guidance document, please contact Elaine Webb, DNREC Sediment and Stormwater Program, 89 Kings Highway, Dover, DE 19901, (302) 739-9921, or email


Elaine Z. Webb

(302) 739-9921

23 DE Reg. 474 (12/01/19) (Gen. Notice)