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Virginia CZM Program: 2013 Coastal Grant Project Description and Final Summary

Project Task:VA CZM logo



Virginia Institute of Marine Science

Project Title:

2013 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 2013, 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 2013 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, as well as any ground truth information submitted to VIMS.  The report will be published on the VIMS web site, as in past years.  SAV polygons will also be available on the VIMS SAV interactive web site (

Federal Funding:


Project Contact:

Robert Orth, 804.684.7392; 

Project Status:

10/1/2013 - 12/31/2014; Project Completed 

Final Product Received:

Final Project Summary serves as Final Product. 

Project Summary Provided by Grantee:

For 2013, 24,164 hectares (24,164 ha) (59,711 acres (59,711 ac)) of SAV were mapped in Chesapeake Bay and its tributaries. Notable changes in SAV distribution were measured between 2013 and 2012. SAV increased 24% from 19,503 ha (48,195 ac) to 24,164 ha (59,711 ac).

The 4,660 ha increase in baywide SAV coverage in 2013 represents a recovery from strong declines in 2011 and 2012 that reduced SAV abundance to a level last reported for the Bay in 1986. The 2013 increase was the result of a strong increase in the Tidal Fresh (743 ha), Mesohaline (2,344 ha), and Polyhaline (1,532 ha) salinity zones and almost no change in the Oligohaline salinity zone (41 ha increase). In 2013, the increases in the Mesohaline and Polyhaline salinity zones are due primarily to a rapid expansion of widgeongrass, including areas where SAV had not been mapped by previous surveys. In addition, we are noting a modest recovery of eelgrass in the polyhaline areas where the hot summers of 2005 and 2010 resulted in dramatic diebacks. The largest SAV bed in the bay, on the Susquehanna Flats in segment CB1TF1, persisted through 2012 and shows an increase in coverage in 2013.

In the Tidal Fresh Bay Zone (19 CBP segments), SAV increased 15% from 4,916 ha (12,148 ac) in 2012 to 5,659 ha (13,985 ac) in 2013. In the Oligohaline Bay Zone (25 CBP segments), SAV increased 2% from 2,230 hectares (5,511 ac) in 2012 to 2,272 hectares (5,613 ac) in 2013. In the Mesohaline Bay Zone (41 CBP segments), SAV increased 30% from 7,939 hectares (19,619 ac) in 2012 to 10,283 hectares (25,410 ac) in 2013. In the Polyhaline Bay Zone (8 CBP segments), SAV increased 35% from 4,418 ha (10,917 ac) in 2012 to 5,950 ha (14,703 ac) in 2013. For 2013, 4,478 hectares (11,065 ac) were mapped in the Delmarva Peninsula Coastal Bays Zone (Assawoman, Isle of Wight, Sinepuxent, Chincoteague, and Southern Virginia coastal bays). Turbid conditions in 2013 prevented us from mapping a small portion of Chincoteague Bay and all of Hog Island, Spidercrab, and Cobb bays, representing 365 ha of SAV in 2012 (954 ac), 8% of the zone total. Comparing the same mapped regions between 2012 and 2013, SAV increased 9% from 4,024 hectares (9,944 ac) in 2012 to 4,400 hectares (10,872 ac) in 2013.

The 2013 SAV report can now be viewed at: and also on our interactive map:

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:

A more detailed Scope of Work for this project is available. Please direct your request for a copy to

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Virginia Department of
Environmental Quality
P.O. Box 1105
Richmond, VA 23218
(804) 698-4000

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