Virginia Institute of Marine Science
2010 Submerged Aquatic Vegetation Distribution and Abundance Survey of Virginia’s Chesapeake Bay and its Tributaries
Project Description as Proposed:
Submerged aquatic vegetation (SAV) is a critical living resource in Chesapeake Bay that has undergone rapid and dramatic baywide fluctuations in distribution and abundance over the last two decades, and is being subjected to declines in water quality and to ever increasing pressure from recreational, commercial, and industrial demands. Because SAV is dependent on good water quality to which it responds over short time scales, it can be an important indicator of water quality. In addition, SAV maps are used via Coastal GEMS as a layer in identifying blue infrastructure so that use conflicts can be avoided and priority conservation areas can be protected. These maps are critical to activities such as the Seaside Special Area Management Plan where marine sptial planning techniques are being used to try to develop more effective coastal policies for the efficient use and protection of marine resources. Aquaculture and other bottom disturbing activities are not allowed in areas with SAV. In 2010, VIMS will continue the annual SAV survey program, begun in 1984, by mapping SAV in the shoal areas of the entire Chesapeake Bay and its tributaries from aerial photography acquired during late spring to late summer. Black & white aerial photography will be acquired at a photographic scale of approximate 1:24,000, following guidelines that address tidal stage, plant growth, sun angle, turbidity, wind, atmospheric transparency, sensor operation and land features to allow for acquisition of photographs under near optimal conditions. Ground data on species distribution and abundance will be collected by participating agencies and citizen groups from as many of the Chesapeake Bay Program segments as possible and included in the final report. The aerial photographs will be evaluated for SAV signatures using all available information. Photographs containing SAV signatures will be orthographically corrected and mosaiced by USGS 7.5 minute topographic quadrangles using Orthobase and Imagine image processing software .
The perimeters of all SAV beds mapped from the 2010 aerial photography will be delineated on-screen using ArcInfo geographic information system (GIS) software and stored in an ArcInfo GIS database. A final report will include maps of all SAV beds, and areas of these beds. The report will be publishedon the VIMS web site, as on past years.
VIMS will maintain and update, as necessary, a Quality Assurance Project Plan detailing the quality control procedures followed to insure proper acquisition of aerial photography and accurate mapping and digitization of data under this scope of work. The contribution of CZM federal funds is for partial financial support of this multi-funded program. Completion of the other tasks required to produce the above deliverables is dependent upon acquiring the remainder of the funds from other state and federal sources. Funding is expected from the Maryland's Department of Natural Resources (from Maryland Coastal Zone Management Grant), and US EPA’s Chesapeake Bay Program.
The results of the annual survey are important for a number of reasons: Virginia Secretary of Natural Resources must report annually on Nov. 1 of each year (effective Oct. 1, 2001) to various Virginia House and Senate Committees the status of SAV abundance from the annual surveys (2.2-220). This measure has specific relevance to implementation of the blue crab fisheries management plan (28.2-203.1). The annual survey has been able to detect major annual changes either from direct impacts (clam dredging) or indirect effects (Tangier Sound SAV losses) shortly after they occur. This information has been used to alert resource managers so that prompt action can be taken. The survey is “the eye in the sky.” The annual survey is becoming critical to the emerging issues of SAV restoration and its effectiveness in rehabilitating sites with no or little SAV. The annual survey will be a critical tool for evaluating progress towards the new SAV restoration goals in the Chesapeake 2000 Agreement. In 2003, the CBP adopted the Strategy to Accelerate the Protection and Restoration of SAV in Chesapeake Bay including a new baywide restoration goal of 185,000 acres by 2010. Progress towards these long-term goals can only be evaluated in the context of detailed inter-annual changes in SAV distribution.
Robert J. Orth, 804.684.7392; firstname.lastname@example.org
10/1/2010 - 12/31/2011
Final Product Received:
Final Project Summary serves as Final Product.
Project Summary Provided by Grantee:
The 2010 distribution of submerged aquatic vegetation (SAV) in the Chesapeake Bay and its tributaries was mapped from black and white aerial photographs. These were taken between May and October 2010, at a scale of 1:24,000, encompassing 173 flight lines.
For 2010, 32,243 hectares (79,675 acres) of SAV were mapped in the Chesapeake Bay and its tributaries. Notable changes in SAV distribution were measured between 2009 and 2010. SAV decreased 7% from 34,768 ha (85,914 ac) to 32,243 ha (79,675 ac). SAV decreased in two (Upper and Middle) and increased in one (Lower) geographic zones delineated for the Chesapeake Bay. In 2010, SAV increased in 23, decreased in 38, and remained unvegetated in 32 of the 93 CBP segments.
The 2,525 ha decrease in baywide SAV coverage in 2010 follows three successive years of increase (2007-2009). This decline occurred primarily in the Middle (1,686 ha) and Upper (908 ha) Bay zones, with the largest losses in two segments in the Middle Bay Zone (Lower Central Chesapeake Bay and Honga River). Widgeongrass, noted for its interannual variability, dominates these segments and much of the Middle Bay Zone. The extremely high summertime temperatures in 2010, one of the warmest years on record, likely killed widgeongrass early in the growing season prior to monitoring. In the Upper Bay Zone, the SAV bed in the Susquehanna Flats, one of the largest SAV beds in the Bay, supports a diverse community of freshwater SAV species and continues to be a major success story for SAV recovery. Surprisingly, despite the very hot temperatures, this bed declined only slightly in 2010. Total SAV coverage in the Lower Bay Zone remained essentially the same following the 2007-2009 increases that were attributed to the recovery of eelgrass after the 2005 dieback.
In the Upper Bay Zone (21 CBP segments extending south from the Susquehanna River to the Chester and Magothy rivers), SAV decreased 10% from 9,549 ha (23,597 ac) in 2009 to 8,641 ha (21,353 ac) in 2010. In the Middle Bay Zone (44 CBP segments extending south from the Bay Bridge to the Rappahannock River and Pocomoke Sound, and including the Potomac River), SAV decreased 11% from 16,030 ha (39,612 ac) in 2009 to 14,344 ha (35,446 ac) in 2010. In the Lower Bay Zone (28 CBP segments covering the region south from the Rappahannock River and Pocomoke Sound regions to the mouth of the Bay), SAV increased 1% from 9,189 ha (22,706 ac) in 2009 to 9,257 ha (22,876 ac) in 2010. In the Delmarva Peninsula Coastal Bays Zone (Assawoman, Isle of Wight, Sinepuxent, Chincoteague, and Southern Virginia coastal bays), SAV increased 7% from 6,862 ha in 2009 to 7,326 ha in 2010.
This report including maps and data showing SAV distribution is available at: http://web.vims.edu/bio/sav/sav10/index.html including an interactive map: http://web.vims.edu/bio/sav/maps.html?svr=www
Disclaimer: This project summary provides the federal dollars initially awarded to the grantee. Due to underexpenditure or reprogramming of grant funds, this figure may change. For more information on the allocation of coastal grant funds, please contact Laura McKay, Virginia Coastal Program Manager, at 804.698.4323 or email: Laura.McKay@deq.virginia.gov
A more detailed Scope of Work for this project is available. Please direct your request for a copy to Virginia.Witmer@deq.virginia.gov