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SECTON 6 – MITIGATION FOR SECONDARY AND CUMULATIVE IMPACTS
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that results from the first inch of precipitation from storm events, and to remove 85 percent
of TSS from stormwater runoff using approved BMPs. These rules are addressed in the
UDO’s stormwater Section 7. All new impervious areas within the Town are being tracked
for future analysis.
6.2.5.5
Neuse River Basin: Nutrient Sensitive Waters Management Strategy (Neuse Basin
Rules)
The buffer requirements of the Neuse Basin Rules are met through the Town’s UDO. The
Town was not named a community for stormwater controls in the Neuse Basin Rules but
does implement these nitrogen control performance standards. The buffer component of
the Neuse Basin Rules do apply though, and is met by the Town’s buffer requirements
discussed previously in Section 6.2. Morrisville is one of only a few municipalities that has
obtained delegation from NCDWR to locally implement the buffer rules.
Cooperative efforts in the Neuse River Basin include the Regional Watershed Plan in the
upper Neuse River Basin. This project, managed by EEP, encompasses 580 square miles
across Wake and Johnston Counties, including the upper Middle Creek and Swift Creek
Watersheds. The goal of this project is to identify and prioritize potential EEP mitigation
projects in the Neuse 01 subwatershed. These projects may include traditional stream and
wetland mitigation as well as buffer restoration; nutrient offset; urban stormwater and
agricultural BMPs; regenerative stormwater conveyances; fish and aquatic organism
passage; aquatic habitat improvements; removal of flow obstructions; and species habitats
preservation or enhancement (NCDENR, 2013b)
6.2.5.6
Jordan Water Supply Nutrient Strategy (Jordan Lake Rules)
The Town is subject to the Jordan Lake Rules, as required by the North Carolina General
Assembly. Nitrogen and phosphorus loads contributed by the proposed new development
will not exceed the following unit-area mass loading rates: 2.2 and 0.82 pounds per acre per
year for nitrogen and phosphorus, respectively. The State has delayed implementation of
the Jordan Rules regarding nutrient management until 2016. However, the Town
voluntarily began implementing the Jordan new development stormwater rules in
February, 2012 throughout the Town’s entire jurisdiction. This is discussed in the UDO
(Section 7.3). The portion of the regulation relating to buffers was not put on hold and
application of this portion has been voluntarily expanded Town-wide. Morrisville is one of
only a few municipalities that has obtained delegation from NCDWR to locally implement
the buffer rules.
As part of the Jordan Lake Rules, the Town initiated the Jordan Lake Stage I Adaptive
Management Strategy Program to address nutrient loading from existing development. In
addition to the measures already in place as a result of the Town's NPDES Phase II permit,
the Town is required annually to identify one potential stormwater BMP retrofit location in
an existing development. NCDWR will determine in the future if the Town will be required
to construct the BMP retrofits that were previously identified.
In 2013, the Town had an assessment performed for Kit Creek watershed in order to
determine potential mitigation opportunities. The assessment considered streams, buffers,
and outfalls, with metrics evaluated including bank stability, sediment deposition, aquatic
habitat, water quality and presence of invasive species (Stantec, 2013).