# Presentation: 308539

## Streamflow and Water-Quality Monitoring in Support of Watershed Model Development, Potomac River Basin

- A Cooperative Project between the
- U.S. Geological Survey and the
- Maryland Department of the Environment

## Problem

- Elevated nitrogen and phosphorus concentrations in the Potomac basin often result from human activities such as manure and fertilizer application (Potomac River NAWQA).
- The monitoring program proposed here is designed to support development of a watershed  model effort to assess the effects of point and nonpoint nutrient and sediment sources on water quality in the Potomac River.

## Objectives

- Restart one inactive stream gage and initiate a new station. Collect stage data for the period of the study according to standard USGS protocols and develop a rating curve for continuous discharge determination.
- Establish nine new water-quality monitoring stations at USGS gaged sites, including those at the new or reactivated gages. Collect and analyze samples (N, P, sediment) at those stations for a period of 18 months.
- Plan, coordinate, and provide oversight for sample collection at all sites by USGS and MDE staff.
- Manage data collected. Plan and provide oversight for quality assurance and quality control for field monitoring at all sites.

## Study Area

- During the first intensive phase of Potomac NAWQA, physiography and geology were determined to be the two most influential natural factors affecting water quality in the basin, and their combination was used to define eight subunits.
- Land use was considered to be the most influential human factor influencing water quality in the basin.

## Subunits

**Subunits**

## Land Use

## Approach

- To determine candidate monitoring sites:
- Existing data were compiled.
- Available data-collection sites (including active and inactive gage sites, with or without water-quality sampling) were grouped by subunit.
- Within each subunit, candidate sites were classified according to their utility as: a) integrator sites; or b) indicator sites, that may be used to calibrate or verify the model for particular land uses within a subunit.
- Candidate sites were prioritized for proposed monitoring.

## Candidate Sites

- 12 integrator sites
- 1 with inactive gage
- 4 with inadequate water-quality data
- 20 indicator sites
- 3 with inactive gages
- 10 with inadequate water-quality data
- 5 main stem sites
- All gaged
- 1 considered for new water-quality monitoring
- TOTAL: 37 sites, 15 candidates for monitoring

## Integrator Sites

**Integrator Sites**

- Subunit Boundaries
- Active Gages
- Proposed Gages
- Priority Sites
- Non-priority Sites

## Indicator Sites

- Subunit Boundaries
- Active Gages
- Proposed Gages
- Priority Sites
- Non-priority Sites

- Mining
- Urban
- Forest
- Agriculture

## Main Stem Sites

## Site Prioritization

- Goals in choosing and prioritizing sites:
- to choose sites that could serve primarily as calibration points for an HSPF model;
- to choose sites that maximized diversity of monitored land uses;
- and to choose sites that could allow for, or create, nesting of monitoring data.

## Site Prioritization

- Coastal Plain sites were considered the highest priority. Other subunits were prioritized such that priority decreased from east to west.
- Integrator and indicator sites in subunits with few or none were given high priority.
- Sites already part of MDE's monitoring effort in western Maryland were considered high-priority.
- Sites that helped meet USGS-WRD goals were considered high-priority.
- Sites close to the main stem Potomac were give higher priority than distal, headwater sites.

## Priority Sites

- The nine highest-priority sites were chosen for the new monitoring effort.
- Of these, two require construction of a new gage at an inactive or new site.
- Data to be collected at these sites over the course of the project are believed to be essential to accurately model watershed hydrological and water-quality processes in the Potomac River Basin.

## Priority Sites

- Subunit Boundaries
- Main Stem Site
- Active Gages
- Proposed Gages

- Urban
- Forest
- Agriculture

## Methods

- Continuous stage and discharge measurement at all sites, including two new/reactivated gages (all real-time).
- Manual scheduled monthly sampling (NAWQA protocols), with automatic samplers collecting additional storm samples.
- Analyses done at NWQL:
- Nutrients (N, P)
- Analyses done at Iowa Sediment Laboratory:
- Total suspended sediments
- Particle size-fraction analysis (selected samples)

## Methods

## Personnel

- Technicians will include USGS staff in Maryland, Virginia, and West Virginia, as well as MDE staff, who will be responsible for assisting in the maintenance and sampling of three sites throughout the duration of the project:
- 01610155, Sideling Hill Creek nr Bellegrove, MD
- 01618000, Potomac River at Shepherdstown, WV)
- 01611500, Cacapon River nr Great Cacapon, WV)

## Timeline