Abstract: Delaware River Rooted Aquatic-Plant Biomass Study from Port Jervis, N.Y. (Route 84 Bridge) to Milford, PA (Route 206 Bridge)
(The complete study is available from DRBC, upon request)
A study on aquatic macrophytes within a 7.7 mile reach of the Delaware River from Port Jervis, New York, to just south of Milford, Pennsylvania. The study objectives were to develop and test effective and efficient biomass measurement techniques; compare the existing biomass density to that measured in 1989 for 5.3 miles of the same study reach; and provide a database for calibration of a stationary-aquatic-plant productivity and water quality model. Square-foot samples of Potamogeton, Elodea, and Vallisneria were collected, dried, and weighed for half-foot plant length intervals from 0.5 to 6 feet. Good relationships were determined for each genus between average plant length and dry weight, and average water depth and average plant length. Relationships were also found for these genus between the root-to-shoot biomass ratio and average plant length. The measured biomass densities were used to estimate the reach-wide biomass densities. Plant beds were selected by genus and average plant length, marked with buoys and delineated for areal coverage with a Global Positioning System (GPS). Most plants were located in a cobble and sand substrate. Fifty-four percent of the biomass was attributable to Vallisneria, 33 percent was from Elodea, and 13 percent was from Potamogeton. The 1989 study showed 5.5 tons more of dry biomass for four of the same reaches in the 1997 study. The difference between 1989 and 1997 water quality data suggests that an additional loading of ammonia near Milford may have propagated this effect.
Contact: Todd Kratzer, DRBC Water Resources Engineer, (609) 883-9500 ext. 261, for more information.
Hydrologic Info | News Releases | Next DRBC Meeting | Other Meetings | Publications | Basin Facts | Contact Info | Your Comments Welcomed
Commission Member Links: Delaware | New Jersey | Pennsylvania | New York | United States |
Voice (609) 883 - 9500 FAX
(609) 883 - 9522 
croberts@drbc.state.nj.us
DRBC
Home Page