Thanks to Mr. Vanderwarker for answering a few questions from our meeting last week:
Here are a few follow-up answers for questions you had on Friday.
· SAND DUNES and SHORE DR. FLOODING FALL 2016
Mr. Damon, your observations are correct. Cape Henry Beach historically had a wider taller dune field and was a “stable” to “accretional” beach for many years. Historically the toe of dune and shoreline position have been slowly advancing bayward over time.
CIP 8-020 Bay Beaches Resiliency was established in the FY 18 CIP to study and address erosion along Cape Henry and Ocean Park beaches. We are in the early study phase. This projects initiates the preliminary planning, design, and permitting framework necessary for instituting a beach management program for Cape Henry and Ocean Park beaches. The project will determine the required beach profile to provide protection to upland structures, apply for State and Federal permits, and development of a funding strategy for a long-term erosion control and storm protection project.
Regarding the lag effect of groundwater that percolated and inundated some parts of Shore Drive in the Fall of ’16; for a storm of this magnitude, we believe there is little to no correlation between the dune erosion and rainfall flooding. Keep in mind that Tropical Storm Hermine and Tropical Storm Julia supersaturated the soils prior to Hurricane Matthew’s arrival just two weeks after Julia. We understand that neither Isabel nor Nor’Ida (Nor’ida having the largest tidal inundation we’ve seen) were as bad as Matthew for this condition. Citizens have also reported the upward movement of groundwater even over at Cape Story By the Sea at the lower elevation properties (3.5 to 4), as there are adjacent higher properties near 10.0. See attached.
If you have any further questions, please direct them to Mr. Dan Adams, Office 757-385-4783 or DAdams@vbgov.com.
· SHORE DRIVE CITY WEBSITE
Yesterday I provided the Project Manager’s name, Mr. Bill Purcell, (757) 385-4887, WPurcell@vbgov.com if you wish to publish just the plan sheets to the website.
· SHORE DRIVE PH III DRAINAGE NEAR THE ROW LINES
For our meeting with the SDCC March 26th, I will bring you a few Shore Dr. PH III plan sheets and cross sections to show how the project handled drainage near the roadway toe of fill areas, and how either supplemental drainage structures were provided or small ditch systems. (Emphasis ours.)
· NEW DITCH TECHNOLOGIES – NEW PRODUCTS TO ENCOURAGE GREEN BUT BE MAINTENANCE FRIENDLY
Ditches will always need maintenance, as sedimentation is a foregone conclusion… But to fulfill both objectives above is very tough… a concrete lined channel may (not always) be easier to maintain for cleaning, but they are not green. If they break up or deteriorate though, a stream restoration project is usually needed to mitigate.
While natural ditches are green, and can grow vegetation, but in this coastal environment they can try to turn into a wetland area.
While some proprietary products are “hybrid” ditches that allow growth “through” concrete blocks and have a protective lining, sediment still has to be removed. During maintenance operations, the danger is that some of the excavator’s bucket “teeth” can grab the material, thus pulling it up, which can be a nightmare since the mats are overlapped (shingled).
PW OPERATIONS did not have new technology solutions that would fit your request.
· ACCEL/DECEL LANE NEAR WESTMINSTER CANTERBURY
There is a proposed dedicated 150’ right turn storage lane with a 150’ taper transition into the Westminster Canterbury site…beyond that entrance, there is continuous accel/decel lane all the way down to Kleen St.
Bradley W. Vanderwarker, P.E.
City of Virginia Beach
PW/Stormwater Eng. Center
2405 Courthouse Drive, Suite 353
Virginia Beach, VA 23456
(757) 385-4131 (main)
(757) 385-8556 (direct)