Publications

Nitrogen (N) and phosphorus (P) are important pollutants that can stimulate nuisance blooms of algae. Water-quality models (e.g., WASP, CE-QUAL-R1, CE-QUAL-ICM, QUAL2k) are valuable and widely used management tools for algal accrual because of excess nutrients in the presence of other limiting factors. These models utilize the Monod and Droop equations to associate algal growth rate with...

Sedimentation in a channel can reduce flood conveyance capability and potentially place nearby property and life at risk from flooding. In 1998, Marin County Public Works dredged the concrete-lined segment of Corte Madera Creek, which drains a hilly and largely urbanized watershed that terminates in San Francisco Bay, California. From then through 2015, approximately 4,100 cubic meters...

Eutrophication problems in the Great Lakes are caused by excessive nutrient inputs (primarily phosphorus, P, and nitrogen, N) from various sources throughout its basin. In developing protection and restoration plans, it is important to know where and from what sources the nutrients originate. As part of a binational effort, Midcontinent SPARROW (SPAtially Referenced Regression On...

Wildfires commonly increase nutrient, carbon, sediment, and metal inputs to streams yet the factors responsible for the type, magnitude and duration of water quality effects are poorly understood. Prior work by the current authors found increased nitrogen, phosphorus and cation exports were common the first five post-fire years from a synthesis of 159 wildfires across the western United...

Accurate estimators of streamflow statistics are critical to the design, planning, and management of water resources. Given increasing evidence of trends in low-streamflow, new approaches to estimating low-streamflow statistics are needed. Here we investigate simple approaches to select a recent subset of the low-flow record to update the commonly used statistic of 7Q10, the annual...

Water quality impairment and land surface subsidence threaten the viability of the Sacramento-San Joaquin Delta (Delta), a critical component of California’s water conveyance system. Current day irrigation drainage through Delta island peat soils impacts drinking water treatment and is linked to mercury transport, potentially posing both ecological and public health concerns. Hybrid...

No abstract available.

Rationale The isotope ratios of nitrogen (15N/14N) and oxygen (18O/16O) in nitrite (NO2−) can be measured by conversion of the nitrite into nitrous oxide (N2O) with azide, followed by mass spectrometric analysis of N2O by gas chromatography isotope ratio mass spectrometry (GC/IRMS). While applying this method to brackish samples, we noticed that the N and O isotope ratio measurements of...

Changing climate has resulted in increasingly unreliable weather patterns with prolonged dry-seasons in some parts of Sub-Saharan Africa. Food production in these areas is under threat because the people depend mostly on rain-fed farming. Enabling dry-season farming, in light of the prolonged dry-seasons, is central to sustainable food production and poverty alleviation in these areas...

We examined the effectiveness of chemically enhanced treatment wetlands (CETWs), wetlands that received water treated with coagulants, to remove dissolved organic carbon (DOC), disinfection byproduct precursors (DBPPs), nutrients and metals from agricultural drain water. Wetlands consisted of controls with no coagulant addition, ferric sulfate dosed and polyaluminum chloride dosed...

Mineralization and historical mining of stibnite (antimony sulfide), tungsten, gold, silver, and mercury in the headwaters of the East Fork of the South Fork Salmon River (EFSFSR) near the former town of Stibnite in central Idaho resulted in water-quality impairments related to mercury, antimony, and arsenic. Additionally, mining-related disturbances and wildfires have resulted in a lack...

Daily mean discharges are needed for rivers in New Hampshire for the management of instream flows. It is impractical, however, to continuously gage all streams in New Hampshire, and at many sites where information is needed, the discharge data required do not exist. For such sites, techniques for estimating discharge are available. The U.S. Geological Survey, in cooperation with the New...