Date: August 31, 2006
To: ACEC-DE Executive Committee/ KC Partnering Committee
From: Tim Anderson
RE: KENT COUNTY PARTNERING MEETING MINUTES- KCD/DNREC
A Kent County partnering
meeting was held with Kent Conservation District (KCD) and DNREC on Wednesday,
August 21, 2006 at 10 a.m. The meeting was attended by the KCD Program Manager,
DNREC Sediment and Stormwater Program Engineers, and three ACEC-DE firm
representatives. The following topics were discussed:
1. Significant changes since the implementation
of the Delaware Sediment and Stormwater Regulations.
KCD is still seeing more conventional ponds than GTBMPs proposed on new projects due to various site limitations on the use of GTBMPs. Bioswales and grass filter strips are the preferred GTBMP in subdivisions in consideration of long term maintenance issues. It was pointed out that GTBMPs are preferred over conventional practices because of the improved stormwater recharge potential via infiltration not because of differences in quality management functions, though infiltration is considered to provide pollutant removal. GTBMPs have been found to be well suited for small commercial sites.
The use of flocculants for sedimentation control during construction has become more common and has been used in swales as well as traps. It has typically been utilized in sediment traps in critical areas or on problem sites.
2. Priority and issues of SWM practices
Groundwater and soil conditions are significant factors that need consideration prior to selection of BMPs and significant design effort of SWM practices. It was discussed that upper level pond benches can typically be waived if 4:1 or flatter slopes are provided above the permanent pool and the slope height is less than 6 feet. Forebays need to be designed and constructed out of gabions or two rows of super silt fence with stone dumped in between.
KCD will express support of a deviation from DelDOT road standards if there is an associated SWM benefit that can be demonstrated.
Statewide bioretention soil testing protocols will soon be issued to enable all suppliers to document the compliance of their soil mixes. Suppliers would have to submit testing documentation on a periodic basis and would have to supply ticket certifications that soil deliveries meet the required specifications.
3. Analysis tools frequently used
Analysis should consider and possibly coordinate with adjacent sites with development plans. Down stream analysis of conveyance restrictions such as pipes need to be considered. TMDL requirements for SWM will become effective for each watershed, one watershed at a time, as the criteria for each watershed is established. The first watershed that will have SWM requirements to meet TMDL standards will be the Inland Bays watershed.
DNREC has filed a start action notice for significant changes to the Delaware Sediment and Stormwater Regulations to address requirements of the Governor’s Surface Water Task Force. Some of the significant changes will be the requirement for runoff volume control. The changes to the regulations will have to go through a significant hearing process and the earliest that the changes are expected to become affective is 2008.
4. Plans and SWM analysis requirements
Areas of needed improvement include plan legibility and clarity and addressing major hydrologic and hydraulic issues. KCD is now using a team approach to the reviews of plans that include a review of the plans by inspector personnel in addition to the engineering reviews.
5. Other
The KCD plan review process was discussed. Some consultants have reported the receipt of review comments that require significant plan changes to address after final construction plans have been submitted. This problem apparently comes about for a couple of reasons: 1) Many of the submissions are poor quality and, for that reason, nearly all of the submissions are treated as such regardless of whether it is a good quality submission or not. The comments for such reviews generally require that certain major items be addressed before a more thorough review is done and therefore all significant issues don’t always receive comment; 2) Critical design criteria, such as groundwater elevations, is often not provided until final plans are submitted, which could result in significant comments being issued after plans are considered to be final.
To resolve these types of problems, meetings are usually helpful. Also, good quality plans should be submitted, which should result in reviews that commensurate with the quality of the plans.
The next Kent County partnering meeting with KCD and DNREC will be held next year, or possibly sooner, to address new trends and practices that come up in the industry.