Open-File Report 99-219 contents page

CHESAPEAKE BAY HABITAT CRITERIA SCORES AND COVERAGE BY SUBMERSED AQUATIC VEGETATION

SAV coverage given in Tables 2 and 3 is also graphically displayed in Figures 2 through 15; SAV coverage for each of the CBP and USGS segments are shown in Figures 2 through 6, and for each of the water quality monitoring station segments in Figures 7 through 15. Also denoted on these figures is an indication when analytical procedures changed and filtered rather than unfiltered samples were used for analysis.

In the freshwater tidal Potomac River segments UTR, LTR and TF2, SAV coverage predominantly corresponds to fluctuations of the Chesapeake Bay habitat scores: SAV coverage tended to increase between years if the scores were predominantly positive and decrease as scores became negative. In the oligohaline Potomac Estuary segment POTOH, the correspondence is more mixed, possibly confounded by the change in analytical procedures. In the mesohaline Potomac Estuary segment POTMH, there appears to be little correspondence to either the sign or the magnitude of the scores. SAV coverage remains minimal, albeit trending positively, throughout this period even though the preponderance of scores is positive. Ongoing propagule studies suggest that lack of seed materials, rather than water-quality conditions, are limiting the regrowth of SAV in this portion of the river.

Patterns in each of the water-quality monitoring station segments shown in Figures 7 through 15 correspond generally to the observations made for the larger salinity zone segments. However, the inter-annual pattern of SAV coverage in the tidal Potomac River station segments suggest that peak growth years show a distinct upstream-downstream gradient, suggested a strong relation to in-stream conditions, rather than external forcing.

The patterns in the Chesapeake Bay habitat criteria scores in relation to SAV coverage in each respective segment indicate that satisfaction of the SAV habitat criteria independently present neither necessary nor sufficient conditions for SAV to occur.

Summary
Chesapeake Bay habitat criteria and scores
Open-File Report 99-219 contents page