Water quality response to a pulsed-flow event on the Mokelumne river, California

2007 ◽  
Vol 23 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Solomon S. Henson ◽  
Dylan S. Ahearn ◽  
Randy A. Dahlgren ◽  
Erwin Van Nieuwenhuyse ◽  
Kenneth W. Tate ◽  
...  
Keyword(s):  
Water Quality ◽  
Pulsed Flow ◽  
Mokelumne River ◽  
Quality Response

scholarly journals Variable impacts of contemporary versus legacy agricultural phosphorus on US river water quality

2019 ◽  
Vol 116 (41) ◽  
pp. 20562-20567 ◽  
Author(s):  
Sarah M. Stackpoole ◽  
Edward G. Stets ◽  
Lori A. Sprague
Keyword(s):  
Water Quality ◽  
Freshwater Ecosystems ◽  
Quality Improvements ◽  
Current Conservation ◽  
Continental Scale ◽  
Crop Uptake ◽  
P Fertilizer ◽  
River Export ◽  
Quality Response ◽  
External P Loading

Phosphorus (P) fertilizer has contributed to the eutrophication of freshwater ecosystems. Watershed-based conservation programs aiming to reduce external P loading to surface waters have not resulted in significant water-quality improvements. One factor that can help explain the lack of water-quality response is remobilization of accumulated legacy (historical) P within the terrestrial-aquatic continuum, which can obscure the beneficial impacts of current conservation efforts. We examined how contemporary river P trends (between 1992 and 2012) responded to estimated changes in contemporary agricultural P balances [(fertilizer + manure inputs)—crop uptake and harvest removal] for 143 watersheds in the conterminous United States, while also developing a proxy estimate of legacy P contribution, which refers to anthropogenic P inputs before 1992. We concluded that legacy sources contributed to river export in 49 watersheds because mean contemporary river P export exceeded mean contemporary agricultural P balances. For the other 94 watersheds, agricultural P balances exceeded river P export, and our proxy estimate of legacy P was inconclusive. If legacy contributions occurred in these locations, they were likely small and dwarfed by contemporary P sources. Our continental-scale P mass balance results indicated that improved incentives and strategies are needed to promote the adoption of nutrient-conserving practices and reduce widespread contemporary P surpluses. However, a P surplus reduction is only 1 component of an effective nutrient plan as we found agricultural balances decreased in 91 watersheds with no consistent water-quality improvements, and balances increased in 52 watersheds with no consistent water-quality degradation.

Post-fire water-quality response in the western United States

2018 ◽  
Vol 27 (3) ◽  
pp. 203 ◽  
Author(s):  
Ashley J. Rust ◽  
Terri S. Hogue ◽  
Samuel Saxe ◽  
John McCray
Keyword(s):  
United States ◽  
Water Quality ◽  
Stream Water ◽  
Western United States ◽  
Change Point Analysis ◽  
Quality Data ◽  
Stream Water Quality ◽  
Nitrogen And Phosphorus ◽  
Water Quality Data ◽  
Quality Response

Wildfires are increasing in size and severity in forested landscapes across the Western United States. Not only do fires alter land surfaces, but they also affect the surface water quality in downstream systems. Previous studies of individual fires have observed an increase in various forms of nutrients, ions, sediments and metals in stream water for different post-fire time periods. In this research, data were compiled for over 24 000 fires across the western United States to evaluate post-fire water-quality response. The database included millions of water-quality data points downstream of these fires, and was synthesised along with geophysical data from each burned watershed. Data from 159 fires in 153 burned watersheds were used to identify common water-quality response during the first 5 years after a fire. Within this large dataset, a subset of seven fires was examined further to identify trends in water-quality response. Change-point analysis was used to identify moments in the post-fire water-quality data where significant shifts in analyte concentrations occurred. Evaluating individual fires revealed strong initial increases or decreases in concentrations, depending on the analyte, that are masked when averaged over 5 years. Evidence from this analysis shows significant increases in nutrient flux (different forms of nitrogen and phosphorus), major-ion flux and metal concentrations are the most common changes in stream water quality within the first 5 years after fire. Dissolved constituents of ions and metals tended to decrease in concentration 5 years after fire whereas particulate matter concentration continued to increase. Assembling this unique and extensive dataset provided the opportunity to determine the most common post-fire water-quality changes in the large and diverse Western USA. Results from this study could inform studies in other parts of the world, will help parameterise and validate post-fire water-quality models, and assist communities affected by wildfire to anticipate changes to their water quality.

Drainage Water Quality Response to Liquid Manure Application

2005 ◽  
Author(s):  
Larry D. Geohring ◽  
Susie Lee ◽  
Peter E. Wright ◽  
T. S. Steenhuis ◽  
M. F. Walter
Keyword(s):  
Water Quality ◽  
Drainage Water ◽  
Liquid Manure ◽  
Manure Application ◽  
Quality Response

Quantifying Annual Nitrogen Loads to Virginia’s Coastal Lagoons: Sources and Water Quality Response

2010 ◽  
Vol 34 (2) ◽  
pp. 297-309 ◽  
Author(s):  
Juliette Christina Poleto Giordano ◽  
Mark J. Brush ◽  
Iris C. Anderson
Keyword(s):  
Water Quality ◽  
Coastal Lagoons ◽  
Nitrogen Loads ◽  
Quality Response

scholarly journals Characteristics of water quality response to hypolimnetic anoxia in Daheiting Reservoir

2021 ◽  
Author(s):  
Chang Liu ◽  
Shiyan Wang ◽  
Xiaobo Liu ◽  
Huaidong Zhou ◽  
Budong Li ◽  
...  
Keyword(s):  
Water Quality ◽  
Joint Effect ◽  
Ammonia Nitrogen ◽  
Water Diversion ◽  
Tianjin City ◽  
Anoxic Environment ◽  
Reducing Substances ◽  
Quality Response ◽  
Water Quality Deterioration ◽  
Iron And Manganese

Abstract Anoxia is a common phenomenon at the bottom of large reservoirs during thermal stratification. In an anoxic environment, an increasing amount of reducing substances and nutrients are released and settle at the hypolimnion of the reservoir, leading to water quality deterioration and eutrophication. This work presents a case study on Daheiting Reservoir, a part of the Water Diversion Project from the Luanhe River to Tianjin City. With the monitored data of the water temperature and dissolved oxygen content in the reservoir, and based on the mechanism of redox reactions, the water quality response to the hypolimnetic anoxia in Daheiting Reservoir was systematically analyzed. It was found that the release of total phosphorus from the sediments in Daheiting Reservoir was a joint effect of the biological and chemical processes, and the redox reaction in the anoxic zone boosted release of phosphorus. Anoxia in the reservoir caused the ammonia nitrogen released from sediments in the reservoir to accumulate at the hypolimnion, which increased the concentration of ammonia nitrogen in the water. Anoxia in the reservoir led to an increase in the concentration of iron and manganese, which accounts for the major driving factor of release of iron and manganese.

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