The full report is too long to post here. Any community member who wishes to receive a copy of the full report should email a request to John Wakeman-Linn at email@example.com.
Spot elevations were measured at the following locations to inform possible solutions. These solutions are somewhat unorthodox and are counterintuitive to earlier recommendations made by Stormwater Maintenance & Consulting. The SMC report recommends clearing/repairing the culverts and regrading the swales to convey the 10-year storm, which is the Anne Arundel County standard for swales along roads of this type. It is clear that the swales and culverts in the community were largely an ad hoc approach to address small, localized ponding issues and were never engineered to meet any drainage standard. Many of these culverts are partially or fully obstructed. The following recommendations, if implemented properly, will improve the performance and reliability of the current drainage network
The intersection of DePriest Drive, Robinson Road, and Al Jones Drive sits is one of the lowest areas of the community and is only a few inches above the Mean High Water (MHW) line at the north end of the marsh. The 8-inch PVC culvert under Al Jones Drive falls 8 inches when passing under the roadway. The community is currently considering paving improvements. As part of those improvements, the following is recommended: elevate this intersection and fill the swale on the southeast corner to pitch drainage across the surface of the road to the north and west; construct a new swale along the west corner of the intersection; and ensure that the corrugated culvert under Robinson Road is in good working order. This may also permit the bioswale along the north side of DePriest to be elevated slightly to improve drainage through the marsh.
Install a catch basin on the end of the culvert to reduce sediment build-up in the culvert. Expand the existing bioretention basin and install an underdrain that ties into the catch basin. Raising the rim of the catch basin above the elevation of the bioretention basin will govern the ponding level and allow pollutants to more effectively be captured in the basin before passing through the culvert. Similar solutions are proposed for the median of Columbia Drive and the bioswale at the west side of the circle.
5224 Al Jones Drive
This section of swale between Baker Road and Lincoln Road is a sump condition, hence the original ponding issue that existed before the bioswales were constructed. Excessively steep side slopes and a high water table prevented the proper construction of these practices, which are now starting to clog the culverts under the front walk and driveway. A continuous underdrain is recommended to run under all three practices, using the driveway culvert as a sleeve, which would then be sealed. This will allow the practices to be elevated and to draw down more effectively.
5309 Al Jones Drive and Crowner Road
Significant ponding occurs on the south side of the intersection, due to a clogged/failing culvert. The BMP on the north side was also constructed at an awkward elevation that has contributed to the clogging of adjacent culverts. A catch basin and underdrain are proposed at the south side of the intersection, along with a new bioretention basin. A check dam is proposed at the north side to keep the swale along Al Jones clear and to increase the elevation of the bioswale, which should be fitted with a continuous underdrain and extended to the east of the existing culvert.
Install a continuous underdrain though the culverts under Bay Drive and the driveway at 1522 Bay Drive. Filtered runoff will drain through the system and discharge to the east side of 1522. Surface overflow and runoff will continue to be directed between 1520 and 1522 Bay Drive, as it currently does now. Reconstruct the bioswales and increase elevation and ponding capacity as practicable. Raise the driveway area and front lawn at 1520 Bay Drive to eliminate ponding.