Maureen Downing-Kunz
Science and Products
Ecosystem Engineers: Impacts of Invasive Aquatic Vegetation on the Delta’s Critical Ecosystems
The Sacramento-San Joaquin Delta (Delta) is home to a diverse community of plants and animals and is the hub of California’s freshwater delivery system. The Delta supplies water for over 25 million Californians and supports millions of acres of farming, commercial and sport fishing, shipping and ports, and recreational boating.
Variability of Salinity and Temperature In San Francisco Bay
The USGS has been collecting specific conductance (salinity) and water temperature data in San Francisco Bay (SF Bay) since 1990. Data are typically collected at 5-10 fixed locations throughout the bay, every fifteen minutes, every minute of the day.
Improved Lower South Bay suspended-sediment flux measurements
Tidal marshes provide animal habitats and prevent erosion. Expanding towns and cities have claimed major parts of San Francisco Bay’s marshland. Sediment deposits are essential to rebuilding tidal marshes and keeping existing marshes intact. In the southern part of the Bay, the largest tidal wetland restoration project on the west coast is underway. Sediment flux measurements are key in...
Understanding Influences on Habitat Quality for Delta Smelt and Other Imperiled Fish Populations
USGS scientists work to provide information needed to evaluate the efficacy of ongoing U.S. Burueau of Reclamation water management efforts in Bay-Delta.
Continuous water-quality and suspended-sediment transport monitoring in the San Francisco Bay, California, water years 2014–15
The U.S. Geological Survey (USGS) monitors water quality and suspended-sediment transport in the San Francisco Bay (bay) as part of a multi-agency effort to address management, water supply, and ecological concerns. The San Francisco Bay area is home to millions of people, and the bay teems both with resident and with migratory wildlife, plants,...
Buchanan, Paul A.; Downing-Kunz, Maureen; Schoellhamer, David H.; Livsey, Daniel N.
Record-high specific conductance and water temperature in San Francisco Bay during water year 2015
The San Francisco estuary is commonly defined to include San Francisco Bay (bay) and the adjacent Sacramento–San Joaquin River Delta (delta). The U.S. Geological Survey (USGS) has operated a high-frequency (15-minute sampling interval) water-quality monitoring network in San Francisco Bay since the late 1980s (Buchanan and others, 2014). This...
Work, Paul A.; Downing-Kunz, Maureen; Livsey, Daniel N.
Review of suspended sediment in lower South Bay relevant to light attenuation and phytoplankton blooms
Lower South Bay (LSB), a shallow subembayment of San Francisco Bay (SFB), is situated south of the Dumbarton Bridge, and is surrounded by, and interconnected with, a network of sloughs, marshes, and former salt ponds undergoing restoration (Figure ES.1). LSB receives 120 million gallons per day of treated wastewater effluent from three publicly...
Schoellhamer, David H.; Shellenbarger, Gregory; Downing-Kunz, Maureen; Manning, Andrew J. Dissolved oxygen: Chapter 6
Dissolved oxygen (DO) concentration serves as an important indicator of estuarine habitat condition, because all aquatic macro-organisms require some minimum DO level to survive and prosper. The instantaneous DO concentration, measured at a specific location in the water column, results from a balance between multiple processes that add or remove...
Senn, David; Downing-Kunz, Maureen; Novick, Emily
Record-high specific conductance and temperature in San Francisco Bay during water year 2014
The U.S. Geological Survey (USGS) has operated a water-quality monitoring network in San Francisco Bay since the late 1980s (Buchanan and others, 2015). This network includes 19 stations in the bay; currently, 8 stations are in operation (fig. 1). All eight stations are equipped with specific conductance (which can be related to salinity) and...
Downing-Kunz, Maureen; Work, Paul; Shellenbarger, Gregory Suspended-sediment dynamics in the tidal reach of a San Francisco Bay tributary
To better understand suspended-sediment transport in a tidal slough adjacent to a large wetland restoration project, we deployed continuously measuring temperature, salinity, depth, turbidity, and velocity sensors in 2010 at a near-bottom location in Alviso Slough (Alviso, California, USA). Alviso Slough is the downstream reach of the Guadalupe...
Shellenbarger, Gregory; Downing-Kunz, Maureen; Schoellhamer, David H. Suspended-sediment trapping in the tidal reach of an estuarine tributary channel
Evidence of decreasing sediment supply to estuaries and coastal oceans worldwide illustrates the need for accurate and updated estimates. In the San Francisco Estuary (Estuary), recent research suggests a decrease in supply from its largest tributaries, implying the increasing role of smaller, local tributaries in sediment supply to this estuary....
Downing-Kunz, Maureen; Schoellhamer, David H. Suspended-sediment dynamics in the tidal reach of a San Francisco Bay tributary
To better understand suspended-sediment transport in a tidal slough adjacent to a large wetland restoration project, we deployed continuously-measuring temperature, salinity, depth, turbidity, and velocity sensors since 2010, and added a dissolved-oxygen sensor in 2012, at a near-bottom location in Alviso Slough (Alviso, California USA). Alviso...
Shellenbarger, Gregory; Downing-Kunz, Maureen; Schoellhamer, David H.
Continuous water-quality and suspended-sediment transport monitoring in the San Francisco Bay, California, water years 2011–13
The U.S. Geological Survey (USGS) monitors water quality and suspended-sediment transport in the San Francisco Bay. The San Francisco Bay area is home to millions of people, and the bay teems with both resident and migratory wildlife, plants, and fish. Fresh water mixes with salt water in the bay, which is subject both to riverine and marine (...
Buchanan, Paul A.; Downing-Kunz, Maureen; Schoellhamer, David H.; Shellenbarger, Gregory; Weidich, Kurt Seasonal variations in suspended-sediment dynamics in the tidal reach of an estuarine tributary
Quantifying sediment supply from estuarine tributaries is an important component of developing a sediment budget, and common techniques for estimating supply are based on gages located above tidal influence. However, tidal interactions near tributary mouths can affect the magnitude and direction of sediment supply to the open waters of the estuary...
Downing-Kunz, Maureen A.; Schoellhamer, David H.