Headwater stream condition and nutrient runoff: Relating SWAT to empirical ecological measures in an agricultural watershed in Pennsylvania

The quantity and quality of available water in the Southeastern United States continues to decline as demands on limited resources increase. Growers will soon be forced to comply with legal limitations on water consumption and limits on nutrient runoff from their operations. A lack of information on standard growing practices using alternative irrigation systems such as ebb and flow is hindering their acceptance and implementation. We are currently conducting a series of experiments to establish basic growing guidelines for the use of ebb and flow in the greenhouse in bedding plant production. In the third of these experiments, Petunia × hybrida Hort. Vilm.-Andr. `Blue Frost' and Begonia × hiemalis Fotsch. `Ambassador Scarlet' were grown for 5 weeks on ebb and flow tables with fertigation solutions (225 ppm N) containing three different levels of phosphorus (0, 50, and 100 ppm). Three soilless media were also used, which varied in their percentage content of vermiculite, perlite, pine bark and coconut coir. For both the begonias and petunias dry mass of the shoot was greatest in plants grown with higher levels of phosphorus. In comparison to plants grown with 0 ppm phosphorous, petunias and begonias grown with 50 or 100 ppm P were 44% and 25% greater in mass, respectively. However, begonias had 38% more flowers when fertigated with the higher levels of phosphorous while petunias flowered earlier with 0 ppm P fertigation solution. The electrical conductivity of the media did not change significantly over the course of the growing period, but the pH dropped by an average of 1 over the same time interval.

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Managing Material Transfer and Nutrient Flow in an Agricultural Watershed

Journal of Environmental Quality ◽

10.2134/jeq2003.0562 ◽

2003 ◽

Vol 32 (2) ◽

pp. 562 ◽

Cited By ~ 2

Author(s):

E. A. Nord ◽

L. E. Lanyon

Keyword(s):

Agricultural Watershed ◽

Material Transfer ◽

Nutrient Flow

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Nutrient Losses and N & P Balances in Small Agricultural Watersheds in Estonia

Hydrology Research ◽

10.2166/nh.2003.0023 ◽

2003 ◽

Vol 34 (5) ◽

pp. 531-542 ◽

Cited By ~ 10

Author(s):

Arvo lital ◽

Enn Loigu ◽

Nils Vagstad

Keyword(s):

Water Quality Monitoring ◽

Agricultural Watersheds ◽

Agricultural Practice ◽

Nutrient Losses ◽

Nutrient Balances ◽

Nitrogen And Phosphorus ◽

Nutrient Runoff ◽

Baltic Countries ◽

Data Loggers ◽

Runoff Regime

The paper deals with nutrient runoff monitoring results and calculated nutrient budgets on catchment level in small agricultural watersheds in Estonia. A special programme for monitoring of nutrient losses was initiated and a network of monitoring stations, equipped with data-loggers and suitable devices for continuous flow measurement and flow-proportional automatic water sampling were established in Estonia in the mid-1990s. The research methodology is harmonized with the Nordic countries as well as with the other Baltic countries. The results indicate that nutrients losses are relatively low (generally below 11 kg N/ha and 0.9 kg P/ha). It can be partly explained by drastic changes in the Estonian agricultural practice in the 1990s but also by differences in runoff regime. Nutrient balances were calculated for two catchments, based on the data collected from the farms, some special studies and water quality monitoring results in two watersheds in 1995 (1999) - 2001. The nutrient balances for the catchments turned positive after being negative both for nitrogen and phosphorus in the mid-1990s.

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Long-Term (15 Years) Results of NPS Controls in an Agricultural Watershed upon a Receiving Lake's Water Quality

Water Science & Technology ◽

10.2166/wst.1993.0447 ◽

1993 ◽

Vol 28 (3-5) ◽

pp. 441-449 ◽

Cited By ~ 8

Author(s):

Paul J. Garrison ◽

Timothy R. Asplund

Keyword(s):

Water Quality ◽

Structural Changes ◽

Soil Phosphorus ◽

Water Clarity ◽

Management Control ◽

Agricultural Watershed ◽

Control Measures ◽

Phosphorus Loading ◽

Phosphorus Concentration ◽

White Clay

Nonpoint source controls were installed in a 1215 ha agricultural watershed in northeastern Wisconsin in the late 1970. Changes were made in handling of animal wastes and cropping practices to reduce runoff of sediment and nutrients. Modelling results predicted a reduction in phosphorus runoff of 30 percent. The water quality of White Clay Lake has worsened since the installation of NPS controls. The lake's phosphorus concentration has increased from a mean of 29 µg L−1 in the late 1970s to 44 µg L−1 in recent years. Water clarity has declined from 2.7 to 2.1 m and the mean summer chlorophyll levels have increased from 9 to 13 µg L−1 with peak values exceeding 40 µg L−1. Increased phosphorus loading is not the result of elevated precipitation but instead the failure of the control measures to sufficiently reduce P loading. Most of the effort was placed on structural changes while most of the P loading comes from cropland runoff. Further, soil phosphorus concentrations have increased because of artificial fertilizers and manure spreading. The White Clay Lake experience is discouraging since the majority of the polluters in this watershed utilized some NPS control practices, including 76 percent of the farms which installed waste management control facilities.

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A renovated model for spatial analysis of pollutant runoff loads in agricultural watershed

Water Science & Technology ◽

10.2166/wst.1998.0403 ◽

1998 ◽

Vol 38 (10) ◽

pp. 207-214 ◽

Cited By ~ 1

Author(s):

Sung Ryong Ha ◽

Dhong Il Jung ◽

Cho Hee Yoon

Keyword(s):

Stream Water ◽

Digital Terrain Model ◽

Pollution Sources ◽

Agricultural Watershed ◽

Water Model ◽

Digital Information ◽

Gis Technology ◽

Terrain Model ◽

Unit Loading ◽

Pollutant Discharge

Runoff loads of pollutant in agricultural watersheds were spatially analyzed by using geographic information system(GIS) technology. The topological relationship between pollution sources in the watershed was, first of all, identified by using the developed digital map of land use and then the pollutant loads generated from each source was estimated by applying a conventional unit loading factor on the obtained digital information of pollution sources. To evaluate the loads delivered from spatially distributed pollution sources to monitoring stations in down stream via surface of watershed, a renovated empirical model incorporated with the information of pollutant discharge path was developed through introducing a digital terrain model(DTM) technique. In this model, the function of degradation of pollution loads during delivery process was simplified so that each watershed could have a basin-wide self-purification capacity which would be considered to be possessed inherently in each watershed and could retard the discharge of pollutants from sources generated to stream water. Model credibility showed good consistency with comparing the simulated values with observed data. Monte Carlo optimizing technique made it possible to estimate the basin-wide self-purification coefficients.

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Evaluation of nutrient runoff from the kako river by continuous daily sampling

Water Science & Technology ◽

10.2166/wst.1996.0305 ◽

1996 ◽

Vol 34 (12) ◽

pp. 67-72

Author(s):

Yukio Komai

Keyword(s):

Suspended Solids ◽

Water Discharge ◽

Electronic Conductivity ◽

High Water ◽

Nutrient Loads ◽

Discharge Condition ◽

Nutrient Runoff ◽

Average Value ◽

Daily Sampling ◽

A Site

A water sample was taken once a day for 15 months at a site near an estuary of the Kako River, Japan, to estimate nutrient loads from rivers to the sea. Total phosphorus (T-P), total nitrogen (T-N), suspended solids (SS) and electronic conductivity (EC) were measured. T-P and SS concentrations varied in proportion to the discharge, and T-P concentrations increased with those of SS, too. EC varied inversely with the discharge, but the fluctuations of T-N concentrations were less than those of T-P and SS concentrations. Water quality remained, for the most part, constant throughout the day. T-P, T-N and SS load were 181t/year, 2320t/year and 51000t/year in 1992, respectively, 54% of T-P load, 47% of T-N load and 80% of SS loads outflowed in those cases where the discharge was more than 100 m3/s, which were 36 days in 1992. 79% of T-P load, 69% of T-N load and 92% of SS load outflowed in periods of high water discharge, which were 88 in 1992. T-P and T-N loads calculated by using one day's data in every month were 151t/year and 2450t/year. But nutrient loads calculated by using the average value of data from an ordinary discharge were two or three times lower than calculated yearly loads. These results showed the importance of estimating the yearly load considering the discharge condition and sampling at a time of high water discharge.

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