**Table 1.** Summary of Chesapeake Bay restoration information needs,
USGS research findings, and restoration applications.

Restoration information need

To understand the effect of long-term changes in climate variability and
man\'s activities on the bay ecosystem.

To better define the sources and transport of nutrients through ground
water.

To reduce nutrients entering the bay to improve dissolved- oxygen
conditions.

To understand the effect of the Susquehanna reservoir system on sediment
delivery to the bay.

To understand changes in sedimentation in the bay and the relation to
water clarity.

USGS research findings

There have been wet and dry cycles over the past 500 years that have
affected the salinity, dissolved oxygen, and water clarity of the bay.
However, these water-quality conditions have severly degraded over the
past 200 years in response to human-induced changes in the watershed.
Human influence and a wet period beginning in 1970\'s may be the
combined causes for dissolved oxygen and water clarity being at their
worst levels in the past 500 years.

The USGS has completed a watershed model that identifies the location of
nutrient sources and their transport to the bay. Ground water was found
to contribute a significant amount of water and nitrogen to streams and
rivers entering the bay.

Although nutrient-reduction actions have been implemented since the
mid-1980's, nutrient loads are not decreasing in the major rivers
entering the bay. Some of the factors responsible are steady or
increasing trends in streamflow and the slow movement of nitrogen
through ground water.

A large amount of sediment is trapped by the reservoirs on the lower
Susquehanna River. Two of the reservoirs have reached their sediment
storage capacity, and the third will reach capacity in 20 to 25 years.
Once the capacity is reached, sediment and phosphorus loads will
increase and degrade water clarity and submerged aquatic vegetation in
the upper bay.

Sedimentation rates in the bay have increased four- to fivefold since
the 1800\'s in response to timber harvesting and increases in
agricultural and urban lands.

Restoration applications

Study results are being used to help set new water-quality standards for
the bay. Results suggest that

restoration efforts may not meet target dates because 200 years of human
influence may not be reversed in 10 years and continued climate
variability may overwhelm restoration activities.

The CBP is working to incorporate the influence of ground water into
management models. Better targeting of locations to achieve nutrient
reduction is being considered on the basis of these model results.

Resource managers are working to accelerate actions because of the slow
improvement in water quality.

A task force with USGS representation was formed to develop and
recommend solutions to prevent the reservoir from reaching its storage
capacity.

This information, along with future studies of the sediment sources
affecting water clarity, will be used by the CBP to develop
sediment-reduction strategies. These scientific findings will be
integrated through a technical workgroup being chaired by the USGS.

To define the factors affecting submerged aquatic vegetation.

To define the occurrence of contaminants in the bay watershed.

To document the effect of contaminants on water birds.

To understand the decline in water bird populations.

To define the factors affecting fish health and the relation to
*Pfiesteria.*

Information was compiled and interpreted for CBP to set light
requirements for SAV in different salinity zones of the bay.
Investigations also showed that presence of SAV-generating materials
(seeds, propagules) is an important factor for survival of SAV. Finally,
investigations revealed that SAV has returned in some areas of the
Potomac but original species have been replaced by species that may not
have the same food and habitat value to water birds and fishery
resources.

Sampling indicates the presence of arsenic and antibiotics in some
rivers. Antibiotics may be reducing microbial populations that break
down nutrients and contaminants.

Initial results from USGS and Fish and Wildlife studies suggest that
pesticide concentrations are below thresholds that cause adverse
reproductive effects for some water birds.

Many of the water bird populations have decreased in the bay watershed
due to loss of SAV and other habitat. Studies showed that some species
have been able to switch from SAV to clams as a primary food source
resulting in more stable populations.

While fish kills are related to *Pfiesteria*, the lesions on menhaden in
the lower Eastern Shore are caused by invasive fungus (*Aphamonyces*
*invadans*). Further investigations are addressing the factors causing
the fish to be susceptible to fungus and *Pfeisteria*.

The information is being used to set water clarity goals and expanded
goals for restoring SAV.

Information will be used in the Toxic-Reduction Effort.

The results are being used to develop strategies for the Toxic Regions
of Concern in the bay watershed (Baltimore Harbor, Anacostia River, and
Elizabeth River).

Results of these and other food-web studies are being used to develop
multispecies management plans for the bay\'s living resources.

Resource managers are using these results to help revise management
practices in the watersheds where *Pfiesteria* has been a concern and to
develop multispecies management plans.

To provide science for ecosystem restoration strategies.

The USGS has now assumed coordination of monitoring and quality
assurance activities at the request of CBP and increased representation
on the technical subcommittees of the CBP.

USGS participation in the CBP provides direct application of science to
formulate and evaluate the effectiveness of ecosystem restoration goals.