Water quality trends in the Delaware River Basin (USA) from 1980 to 2005

Kauffman, Gerald J.; Homsey, Andrew; Belden, Andrew C.; Sanchez, Jessica Rittler

doi:10.1007/s10661-010-1628-8

Cited by 25 publications

(23 citation statements)

References 12 publications

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“…Daily discharge was defined as the average discharge recorded per day during the last 4 yr (2006–2010, entire duration of records). The concentration of N (3.13 mg L −1 ) was estimated for the watershed using a forest cover (23.15%) linear regression model developed for the Delaware River basin (Kauffman and DeSisto, 2006; Kauffman et al, 2011). We calculated the area and land cover classes of the watershed upstream of the study site by delineating 30‐m‐resolution DEMs.…”

Section: Methodsmentioning

confidence: 99%

Exchange of Nitrogen through an Urban Tidal Freshwater Wetland in Philadelphia, Pennsylvania

Elsey‐Quirk

Smyth²,

Piehler³

et al. 2013

J. Environ. Qual.

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Tidal freshwater wetlands in urban settings can be subject to elevated N concentrations, which can promote the exchange of N between the marsh, water, and atmosphere, including denitrification. We used a multitiered approach consisting of direct measurements of N fluxes and denitrification, tidal hypsometry, and N load modeling to examine N exchanges in an urban tidal freshwater wetland of the Delaware River Estuary, Philadelphia, PA. Sediment cores and aboveground biomass were collected at 20 locations across a range of elevations and plant communities in April, July, and October 2010. Nitrate was taken up by the marsh during all seasons. In the spring, the high rate of NH production from the sediment was correlated with NO uptake, suggesting dissimilatory reduction to NH as a potentially important process. Denitrification rates were greatest in July, averaging 5.5 ± 0.6 mg N m h. Adjusted for tidal inundation using a refined digital elevation model, denitrification averaged 0.08, 0.5, and 0.2 g N m mo for April, July, and October, respectively. Less than 10% of the modeled N load was estimated to have been removed in the months measured. A combination of high N load, limited marsh area that represented ∼1% of the watershed area, and conservative extrapolation of denitrification rates contributed to the low estimate of the N load attenuated.

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Section: Methodsmentioning

confidence: 99%

Exchange of Nitrogen through an Urban Tidal Freshwater Wetland in Philadelphia, Pennsylvania

Elsey‐Quirk

Smyth²,

Piehler³

et al. 2013

J. Environ. Qual.

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“…The Delaware Basin covers just 0.4% of the continental U.S., yet supplies drinking water to 5% of the nation's population and the first (New York City) and seventh (Philadelphia) largest metropolitan economies in the nation [23]. Over 16 million people rely on the Delaware Basin for drinking water, including 8.2 million people who live in the watershed and 8 million people who live outside the basin in New York City and central New Jersey.…”

Section: The Delaware Rivermentioning

confidence: 99%

The Cost of Clean Water in the Delaware River Basin (USA)

Kauffman

2018

Water

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Abstract:The Delaware River has made a marked recovery in the half-century since the adoption of the Delaware River Basin Commission (DRBC) Compact in 1961 and passage of the Federal Clean Water Act amendments during the 1970s. During the 1960s, the DRBC set a 3.5 mg/L dissolved oxygen criterion for the river based on an economic analysis that concluded that a waste load abatement program designed to meet fishable water quality goals would generate significant recreational and environmental benefits. Scientists with the Delaware Estuary Program have recently called for raising the 1960s dissolved oxygen criterion along the Delaware River from 3.5 mg/L to 5.0 mg/L to protect anadromous American shad and Atlantic sturgeon, and address the prospect of rising temperatures, sea levels, and salinity in the estuary. This research concludes, through a nitrogen marginal abatement cost (MAC) analysis, that it would be cost-effective to raise dissolved oxygen levels to meet a more stringent standard by prioritizing agricultural conservation and some wastewater treatment investments in the Delaware River watershed to remove 90% of the nitrogen load by 13.6 million kg N/year (30 million lb N/year) for just 35% ($160 million) of the $449 million total cost. The annual least cost to reduce nitrogen loads and raise dissolved oxygen levels to meet more stringent water quality standards in the Delaware River totals $45 million for atmospheric NOX reduction, $130 million for wastewater treatment, $132 million for agriculture conservation, and $141 million for urban stormwater retrofitting. This 21st century least cost analysis estimates that an annual investment of $50 million is needed to reduce pollutant loads in the Delaware River to raise dissolved oxygen levels to 4.0 mg/L, $150 million is needed for dissolved oxygen levels to reach 4.5 mg/L, and $449 million is needed for dissolved oxygen levels to reach 5.0 mg/L.

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“…The Christina River basin has 7.8% impervious surfaces and a population density of 1764/km. The basin is 30% developed, 32% forested, and 37% agricultural (Kauffman et al, 2008). The underlying bedrock consists of Cambrian metamorphic rocks of the Wissahickon Formation (Schenck et al, 2000) and Ordovician metamorphic rocks of the Faulkland gneiss and Windy Hill gneiss (Schenck et al, 2000).…”

Section: Study Areamentioning

confidence: 99%

“…The mean annual precipitation in the watershed is 116 cm (Kauffman et al, 2008). Intense precipitation events are usually delivered by thunderstorms, hurricanes, or nor'easters (cyclonic storm occurring along the east coast of North America and named because the winds are from the northeast; Huschke, 1959).…”

Section: Study Areamentioning

confidence: 99%

“…Construction of mill dams began as early as 1802 when the DuPont family settled in the area (Kauffman et al, 2008). At the height of mill dam construction, there may have been hundreds of operating mill dams in the watershed (Walter and Merritts, 2008), but only 72 mill dams are currently in place in the subwatersheds of the Christina River, Brandywine River, White Clay Creek, Red Clay Creek, and Naamans Creek (Kauffman et al, 2008).…”

Section: Study Areamentioning

confidence: 99%

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Bedload transport over run-of-river dams, Delaware, U.S.A.

Pearson

Pizzuto

2015

Geomorphology

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We document the detailed morphology and bed sediment size distribution of a stream channel upstream and downstream of a 200-year-old run-of-river dam on the Red Clay Creek, a fifth order stream in the Piedmont of northern Delaware, and combine these data with HEC-RAS modeling and bedload transport computations. We hypothesize that coarse bed material can be carried through run-of-river impoundments before they completely fill with sediment, and we explore mechanisms to facilitate this transport. Only 25% of the accommodation space in our study site is filled with sediment, and maximum water depths are approximately equal to the dam height. All grain-size fractions present upstream of the impoundment are also present throughout the impoundment. A characteristic coarse-grained sloping ramp leads from the floor of the impoundment to the crest of the dam. A 2.3-m-deep plunge pool has been excavated below the dam, followed immediately downstream by a midchannel bar composed of coarse bed material similar in size distribution to the bed material of the impoundment. The mid-channel bar stores 1472 m 3 of sediment, exceeding the volume excavated from the plunge pool by a factor of 2.8. These field observations are typical of five other sites nearby and suggest that all bed material grain-size fractions supplied from upstream can be transported through the impoundment, up the sloping ramp, and over the top of the dam. Sediment transport computations suggest that all grain sizes are in transport upstream and within the impoundment at all discharges with return periods from 1 to 50 years. Our computations suggest that transport of coarse bed material through the impoundment is facilitated by its smooth, sandy bed. Model results suggest that the impoundment is currently aggrading at 0.26 m/year, but bed elevations may be recovering after recent scour from a series of large floods during water year 2011-2012. We propose that impoundments upstream of these run-of-river dams behave as long pools that adjust their bed elevation and texture to transport the load supplied by the watershed, rather than as impounded reservoirs with little bed material transport capacity. Scour may only occur during episodic high flows, followed by aggradation during periods of low flow.

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Water quality trends in the Delaware River Basin (USA) from 1980 to 2005

Cited by 25 publications

References 12 publications

Exchange of Nitrogen through an Urban Tidal Freshwater Wetland in Philadelphia, Pennsylvania

Exchange of Nitrogen through an Urban Tidal Freshwater Wetland in Philadelphia, Pennsylvania

The Cost of Clean Water in the Delaware River Basin (USA)

Bedload transport over run-of-river dams, Delaware, U.S.A.

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