Recent Submissions

  • R/V Oceanus Cruise #473 ‘Ocean Acidification Pteropod Study’ Cruise Report

    Lawson, Gareth; Wiebe, Peter; Wang, Zhaohui Aleck; Lavery, Andone; Maas, Amy Elizabeth; Blanco-Bercial, Leocadio; Hoering, Katherine A.; Copley, Nancy; Fincke, Jonathan; White, Timothy; et al. (2011)
    The central goal of this cruise was to sample various aspects of the biology of pteropods and other associated zooplankton concurrent to sampling of the carbonate chemistry system and hydrography, both along-track and at pre-defined stations along a survey transect extending from 35N, 52W to 50N, 42W.
  • R/V New Horizon Cruise #1208 ‘Ocean Acidification Pteropod Study’ Cruise Report

    Lawson, Gareth; Wiebe, Peter; Wang, Zhaohui Aleck; Lavery, Andone; Maas, Amy Elizabeth; Copley, Nancy; Blanco-Bercial, Leocadio; Hoering, Katherine A.; Bolmer, Tom; Chu, Sophie; et al. (2012)
    The central goal of this cruise was to sample various aspects of the biology of pteropods and other associated zooplankton concurrent to sampling of the carbonate chemistry system and hydrography, both along-track and at pre-defined stations along a survey transect extending from 50N, 150W to 35N, 135W.
  • Preliminary Stock Structure of Coastal Bottlenose Dolphins along the Atlantic Coast of the US

    Southeast Fisheries Science Center, National Marine Fisheries Service (U.S.) (2001-06)
    Recent analyses have identified multiple stocks of bottlenose dolphins along the Atlantic coast from New Jersey to central Florida. Although drawing stock boundaries is confounded by the migratory pattern of the northernmost stock and by the unequal distribution of samples both spatially and temporally, results to date indicate the likelihood of a high level of structuring. In order to estimate abundance, the offshore range of the coastal morphotype of bottlenose dolphin also has been tentatively identified. That range is different north and south of Cape Hatteras; north of Cape Hatteras, evidence suggests that the coastal morphotype generally inhabits a range from the coast to 12km from shore, while south of Cape Hatteras, the range extends to 27km. Using both sets of results (latitudinal and longitudinal), management units can be defined for the purpose of evaluating the potential effects of fisheries mortality: 1. Northern Migratory Unit: In summer, this stock is found primarily from the NC/VA state line to the northern limit of the range (NJ or NY). In winter, this stock migrates out of the northern coastal areas and at least some of the animals are found off the coast of NC, where they spatially overlap with the northern and southern NC units. 2. Northern NC Unit: In summer, this unit consists of dolphins along the coast of NC from Cape Lookout to the VA/NC line and dolphins that reside in northern estuaries in this region. There is some evidence of dolphins moving between estuaries and the coast. There may also be spatial overlap between this unit and the southern NC unit in summer, at least in the estuaries near Cape Lookout. In winter, this unit occurs along the coast or estuaries of NC, where it spatially overlaps with the migratory unit and the southern NC unit. 3. Southern NC Unit: In summer, dolphins in this unit are found primarily along the coast of NC from south of Cape Lookout, NC, to Murrell's Inlet, SC. There may also be spatial overlap between this unit and the northern NC unit in summer, at least in the estuaries near Cape Lookout. In winter, these dolphins are assumed to be in the same areas, where they may spatially overlap with the migratory unit and with the Northern NC unit. 4. South Carolina Management Units: This management unit encompasses dolphins south of Murrell’s Inlet, SC, (the southern NC Unit) and the SC/GA state line. Seasonal movements that might result in spatial overlap between this stock and any others have not been defined. 5. Georgia Management Unit: This management unit encompasses dolphins in coastal and estuarine waters of Georgia. Seasonal movements that might result in spatial overlap between this stock and any others have not been defined. 6. Northern Florida Management Unit: This management unit includes dolphins from the FL/GA state line to the north end of the Indian/Banana River Lagoon system. 7. Central Florida Management Unit: This management unit begins south of the northern management unit and has an undefined southern boundary because of lack of information south of the Indian/Banana River system. However, consistent with results from areas to the north, it is precautionary to assume that this stock does not range as far south as southern Florida.
  • Taxonomic review and meristic variation in marine sculpins (Osteichthyes:Cottidae) of the northeast Pacific Ocean

    Howe, Kevin M.; Richardson, Sally L. (U.S. NOAA National Marine Service, Northwest and Alaska Fisheries Center, 1978-09-30)
    Within the northeast Pacific Ocean (Baja California to the Aleutian Islands), 40 genera comprising 90 species of sculpins (Cottidae) have been recorded; this includes two members of the freshwater genus Cottus which are often found in nearshore marine waters. The species are listed and their distributions are indicated. At present, only one family, Cottidae, should be recognized for the sculpins. Each genus is discussed in terms of taxonomic problems and affinities and each is also diagnosed, indicating differentiating characteristics. Some genera should be synonymized and these are indicated although no formal synonymies are proposed at this time. In addition, other genera need to be studied as they appear closely related to other genera and might be synonymized without any loss of information. The species in some genera (i.e. Artediellus, Hemitripterus, Icelinus, Icelus, Malacocottus, Myoxocephalus, Triglops) are in serious need of study. Some of the species within these genera, as well as many species in other genera are noticably rare in museum collections. Each species within the northeast Pacific is also diagnosed and comments on depth distribution and relative rarity are provided. Meristic data compiled from museum specimens is provided for each genus as well as each species. Artificial keys to the cottid genera and cottid species in the northeast Pacific Ocean are included.
  • Young Scholars Cruise Report: Data Report: CTD and Hydrographic Data, R/V Pelican Cruise, July 1-4, 1993.

    Toon, R.; Shah, S.; Toler, E. (Louisiana Universities Marine Consortium, 1993-07)
    Louisiana Young Scholars in Marine Science is a program supported by the National Science Foundation and the LUMCON Foundation, Inc. Ten students who have completed their junior year of high school and are entering their senior year were selected on scholastic merit for the program in the summer of 1993. As a part of this program, a 3-day research cruise was held aboard the R/V Pelican. The purpose of the cruise was two-fold: 1) to acquaint the students with some oceanographic sampling techniques and procedures; and 2) to characterize water column properties in different regions of the northern Gulf of Mexico. This report summarizes the results of this cruise.
  • Zooplankton Community Characterization: Oceanic and Shelf Transect (ZCCOAST) Data Report: CTD and Hydrographic Data, Zooplankton Counts, R/V Pelican Cruise, June 25-27, 1991.

    Toon, R.; Dagg, Michael J.; D'Agrosa, C.; Solet, D. (Louisiana Universities Marine Consortium, 1993-05)
    The purpose of this cruise was to characterize the zooplankton community across the continental shelf and into the oceanic Gulf of Mexico. Five stations due south of the sea buoy off of Cocodrie (LA) were selected at approximately the 25, 50, 100, 400, and 600 fathom contours. At each station a CTD cast was done to acquire hydrographic data. At the time of each cast, water was also collected for pigment and nutrient analyses. Also, at each station, net tows were done for zooplankton collection.
  • DOE Coastal Ocean Program: "Assimilation and Transfer of Carbon in Oligotrophic and Eutrophic Coastal Water Columns" Data Report: CTD and Hydrographic Data, R/V Pelican Cruise no. 92-10, October 19-27, 1992.

    Toon, R.; Dagg, Michael J. (Louisiana Universities Marine Consortium, 1992-12)
    Water column processes were examined in two environments within the continental margin of the northern Gulf of Mexico. Location I was at the shelf break and location II was at the inner to mid shelf. Each location was first characterized by a brief mapping exercise with the ship's flow-through monitoring system called MIDAS. This system monitors surface water conditions of temperature, salinity, chlorophyll fluorescence and light transmission. Each is plotted as a function of the ship's cruise track, providing a real time image of surface water properties. CTD profiles provided vertical resolution at selected sites. At each location, the information provided by the mapping output and CTD was used to select a location for deployment of a floating sediment trap array. At the slope location, traps were set at 65 m and 90 m. At the inner shelf station, traps were set for 17 m and 25 m. In both cases, water column processes in the vicinity of the drifting trap array were characterized over a 2 day deployment. During each trap deployment, depth profiles of temperature, salinity, chlorophyll and nutrient concentrations were made several times a day. Process measurements included phytoplankton primary production, P I properties and growth rate, bacterial production, water column respiration, microzooplankton grazing (2 methods), and mesozooplankton grazing (2 methods). At each location, additional water column measurements included: DOC profiles; quantification of dissolved carbohydrates; isolation and characterization of dissolved organic matter; phytoplankton pigments; irradiance profiles; and POC/PON. A budget of water column processes will be constructed at each of the two environmentally distinct deployment sites to determine carbon inputs, rates of recycling and fates within the upper water column.
  • DOE Coastal Ocean Program: Cruise in Support of Proposal Titled "Assimilation and Transfer of Carbon in Oligotrophic and Eutrophic Coastal Water Columns", Data Report: CTD and Hydrographic Data, R/V Pelican Cruise no. PE930504, May 5 - May 13, 1993.

    Toon, R.; Dagg, Michael J. (Louisiana Universities Marine Consortium, 1993-08)
    Water column processes were examined in two environments within the continental margin of the northern Gulf of Mexico. Location I was at the shelf break/slope and location II was at an inner to mid shelf location. Each location was first characterized by a brief mapping exercise done with the ship's flow-through monitoring system called MIDAS. This system monitors surface water conditions of temperature, salinity, chlorophyll fluorescence and light transmission. Each is plotted as a function of the ship's cruise track, providing a real time image of surface water properties. CTD profiles were used to provide vertical resolution at selected sites during the map. At each location, the information provided by the mapping output and CTD drops was used to select a location for deployment of a floating sediment trap array. Traps were set for 2 depths. At the slope location, traps were set for 65 m and 90 m. At the inner shelf station, traps were set for 17 m and 25 m. At the slope station, water column processes at the trap site was measured over a 3 day duration during which the trap array was tracked by the vessel. At the mid-shelf site, the traps were deployed for two days. During each trap deployment, hydrographic measurements were measured four times a day with the CTD. Depth profiles of chlorophyll and nutrient concentrations were made for each cast. Process measurements included phytoplankton production and P vs. I curves, bacterial production, water column respiration, microzooplankton grazing (2 methods), and mesozooplankton grazing (2 methods). At each location, additional water column measurements included: DOC profiles; quantification of dissolved carbohydrates; and isolation and characterization of dissolved organic matter. A budget of water column processes will be compared with vertical flux measured by sediment traps at each site to determine what fraction of production is recycled within the photic zone and whether recycling efficiency varies between sites.
  • Young Scholars Cruise Report: Data Report: CTD and Hydrographic Data, R/V Pelican Cruise, July 2-5, 1992.

    Toon, R.; Konikoff, M.; McNabb, B.; Louisiana Universities Marine Consortium (Louisiana Universities Marine Consortium, 1992-07)
    Louisiana Young Scholars in Marine Science is a program supported by the National Science Foundation and the LUMCON Foundation, Inc. Ten students who have completed their junior year of high school and are entering their senior year were selected on scholastic merit for the program in summer of 1992. As a part of this program, a 3-day research cruise was held aboard the R/V Pelican. The purpose of the cruise was two-fold: 1) to acquaint the students with some oceanographic sampling techniques and procedures; and 2) to characterize water column properties in different regions of the northern Gulf of Mexico. This report summarizes the results of this cruise.
  • LaSER Oceanography: Data Report Number 6, R/V Pelican Cruise, October 23-29, 1990, CTD and Hydrographic Data

    Toon, R.; Dagg, Michael J.; Louisiana Universities Marine Consortium (Louisiana Universities Marine Consortium, 1991-02)
    This five year multi-institutional and multi-investigator program is entitled "Oceanographic Processes on Continental Shelves Influenced by Large Rivers." Funding began in January, 1987. The scientific goals of this program are a) investigations on a large spatial scale, from the Mississippi River delta to some far field (down-plume) location, to examine biological responses to riverine inputs of dissolved nutrients, suspended sediments, and fresh water; b) investigations on small spatial scales, both horizontally and vertically, in a cross plume direction to examine the role of oceanographic fronts, convergences, and discontinuities in biological production; and c) investigations on small temporal scales, particularly to examine the biological responses to the passage of winter storms. This report summarizes the CTD and hydrographic data from the sixth LaSER oceanography cruise, for the Mississippi River plume region west of the delta.
  • Nutrient Enhanced Coastal Ocean Productivity (NECOP): Data Report: CTD and Hydrographic Data, R/V Pelican Cruise, May 5-17, 1992.

    Toon, R.; Dagg, Michael J.; Louisiana Universities Marine Consortium (Louisiana Universities Marine Consortium, 1992-08)
    The Nutrient Enhanced Coastal Ocean Productivity (NECOP) Program is a component of NOAA's Coastal Ocean Program. The central hypothesis of this research is: anthropogenic nutrient inputs have enhanced coastal ocean productivity with subsequent impacts on coastal ocean water quality, living resource yields, and the global marine carbon cycle. The initial study area for this program is the Mississippi/Atchafalaya River Outflow and adjacent Louisiana shelf region. The focus of this cruise, P26-92, was on water column processes particularly phytoplankton, bacterial, and zooplankton processes as they relate to particulate flux. To accomplish these objectives we visited the plume region, the hypoxia region and a blue water region well offshore. In each region, the surface water was initially characterized by use of a flow-through mapping system aboard the vessel Pelican, the MIDAS system. In addition an ADCP system was deployed during portions of the cruise. Within the plume and hypoxia regions, work was accomplished while following free floating sediment traps over 48 hour periods. In addition to routine hydrographic sampling (CTD, nutrients, chlorophyll, suspended particulate matter) experimental measurements of phytoplankton production, bacterial production, zooplankton biomass and zooplankton feeding rates were made at appropriate intervals while tracking the sediment traps. This report summarizes the CTD and basic hydrographic measurements made during the cruise.
  • Nutrient Enhanced Coastal Ocean Productivity (NECOP) Data Report: CTD and Hydrographic Data, R/V Pelican Cruise, September 12-18, 1991

    Toon, R.; Dagg, Michael J. (Louisiana Universities Marine Consortium, 1992-01)
    The Nutrient Enhanced Coastal Ocean Productivity (NECOP) Program is a component of NOAA's Coastal Ocean Program. The central hypothesis of this research is: Anthropogenic nutrient inputs have enhanced coastal ocean productivity with subsequent impacts on coastal ocean water quality, living resource yields, and the global marine carbon cycle. The initial study area for this program is the mississippi/Atchafalaya River Outflow and adjacent Louisiana shelf region. NECOP cruises I and II were in July/August 1990 and March 1991. The focus of this cruise, NECOP III, was on water column processes particularly phytoplankton, bacterial, and zooplankton processes as they relate to particulate flux. To accomplish these objectives we visited the plume region, the hypoxia region and a blue water region well offshore. In each region, the surface water was initially characterized by use of a flow-through mapping system aboard the vessel PELICAN, the MIDAS system. In addition an ADCP system was deployed with a different frequency being selected for each region. The high Frequency (1200 khz) transducer was used in the plume region, the mid-frequency (600 khz) transducer in the hypoxia region and the low frequency (300 khz) system in the offshore region. Within the plume and hypoxia regions, work was accomplished while following free floating sediment traps over 36-48 hour periods. In addition to routine hydrographic sampling (CTD, nutrients, chlorophyll, suspended particulate matter) experimental measurements of phytoplankton production, bacterial production, phosphorus uptake and turnover, zooplankton biomass and zooplankton feeding rates were made at appropriate intervals while tracking the sediment traps. This report summarizes the CTD and basic hydrographic measurements made during the cruise.
  • LaSER Oceanography: Data Report Number 5, R/V Pelican Cruise, April 23-29, 1990, CTD and Hydrographic Data

    Toon, R.; Dagg, Michael J. (Louisiana Universities Marine Consortium, 1990-08)
    This five year multi-institutional and multi-investigator program is entitled "Oceanographic Processes on Continental Shelves Influenced by Large Rivers." Funding began in January, 1987. The scientific goals of this program are a) investigations on a large spatial scale, from the Mississippi River delta to some far field (downplume) location, to examine biological responses to riverine inputs of dissolved nutrients, suspended sediments, and fresh water; b) investigations on small spatial scales, both horizontally and vertically, in a cross plume direction to examine the role of oceanographic fronts, convergences, and discontinuities in biological production; and c) investigations on small temporal scales, particularly to examine the biological responses to the passage of winter storms. This report summarizes the CTD and hydrographic data from the fifth LaSER oceanography cruise, for the Mississippi River plume region west of the delta.
  • LaSER Oceanography: Data Report Number 4, R/V Pelican Cruise, September 20-27, 1989, CTD and Hydrographic Data

    Toon, R.; Dagg, Michael J. (Louisiana Universities Marine Consortium, 1990-01)
    This five year multi-institutional and multi-investigator program is entitled "Oceanographic Processes on Continental Shelves Influenced by Large Rivers." Funding began in January, 1987. The scientific goals of this program are a) investigations on a large spatial scale, from the Mississippi River delta to some far field (down-plume) location, to examine biological responses to riverine inputs of dissolved nutrients, suspended sediments, and fresh water; b) investigations on small spatial scales, both horizontally and vertically, in a cross plume direction to examine the role of oceanographic fronts, convergences, and discontinuities in biological production; and c) investigations on small temporal scales, particularly to examine the biological responses to the passage of winter storms. This report summarizes the CTD and hydrographic data from the fourth LaSER oceanography cruise, for the Mississippi River plume region west of the delta.
  • LaSER Oceanography: Data Report Number 3, R/V Pelican Cruise, April 10-22, 1989, CTD and Hydrographic Data

    Toon, R.; Dagg, Michael J. (Louisiana Universities Marine Consortium, 1989-10)
    This five year multi-institutional and multi-investigator program is entitled "Oceanographic Processes on Continental Shelves Influenced by Large Rivers." Funding began in January, 1987. The scientific goals of this program are a) investigations on a large spatial scale, from the Mississippi River delta to some far field (down-plume) location, to examine biological responses to riverine inputs of dissolved nutrients, suspended sediments, and fresh water; b) investigations on small spatial scales, both horizontally and vertically, in a cross plume direction to examine the role of oceanographic fronts, convergences, and discontinuities in biological production; and c) investigations on small temporal scales, particularly to examine the biological responses to the passage of winter storms. This report summarizes the CTD and hydrographic data from the third LaSER oceanography cruise, for the Mississippi River plume region west of the delta.
  • Toxic Chemicals and Biological Effects in Puget Sound: Status and Scenarios for the Future

    Quinlan, E. A.; Chapman, P. M.; Dexter, R. N.; Konasewich, D. E.; Ebbesmeyer, C. C.; Erickson, G. A.; Kowalski, B. R.; Silver, T. A. (U.S. Department of Commerce, National Oceanic and Atmospheric Administration, 1985)
  • McMullin On-Farm Flood Capture and Recharge Project: Hydrologic and Hydraulic Analyses (H&H), final report

    Bachand, P.A.M.; Trabant, S.; Vose, S.; Mussetter, B. (Kings River Conservation District, 2014-01)
    Approval of a Hydrologic and Hydraulic Analyses (H&H) by California Department of Water Resources (DWR) is a pre-requisite for projects being funded through DWR’s Flood Corridor Program. The H&H needs to show early in the project schedule in analysis acceptable to DWR that the project will produce the anticipated flood risk reduction benefits. A Benefit:Cost (B/C) ratio provides a metric for comparing benefits from a project in relation to DWR costs for the project. In our analysis, we calculated a B/C of 1.86 for Phase 1, the diversion of 150 cubic feet per second (cfs) from the Kings River onto the project during flood flow conditions between December and May, and of 1.98 for Phase 2/3, the diversion of 500 cfs from the Kings River onto the project during the same conditions. We provide background on the project and the area that will be affected by the project (the study area), summarize our methods, and present our findings.Two large hydrologic issues face the Kings Basin: severe and chronic overdraft of about 0.16M ac-ft annually, and flood risks along the Kings River and the downstream San Joaquin River. Since 1983, downstream communities along the Kings and San Joaquin Rivers have suffered over $1B in flood damages (2013$). To help mitigate these two issues, this project proposes diverting and capturing Kings River floodwater at the James Bypass onto agricultural lands adjacent to the Kings River for conjunctive use purposes (e.g. recharge, in lieu recharge, irrigation). This project is planned in three phases: Phase 1 (Ph1) will divert 150 cubic feet per second (cfs) onto agricultural fields from December through May and 100 cfs from June through September. Fifty-five hundred acres are planned for enrollment in Ph1 with 375 acres under flood easements; 1,125 acres managed under dual purpose of accepting flood flows and being managed for farming; and the remaining acreage receiving flood flows when available for in lieu recharge. Phases 2 and 3 (Ph 2/3) together will expand enrollment to 16,000 acres with expected equivalent ratios for flood easements, dual purpose and farming. Ph2/3 is planned to have a 500 cfs flood diversion and capture capacity. We assessed hydrologic and hydraulics conditions and economics for these planned phases following the scope of work defined in Task Order 1 between Kings River Conservation District (KRCD) and Tetra Tech.
  • On-Farm Flood Capture and Recharge (OFFCR) at an Organic Almond Orchard, Recharge Rates and Soil Profile Responses Groundwater Recharge Project, 2016

    Bachand, S.M.; Carlton, S.; Bachand, P.A.M. (Sustainable Conservation, 2017-04-18)
    Groundwater in much of California’s Central Valley (CV) has been critically over-drafted resulting in the implementation of the 2014 Sustainable Groundwater Management Act (SGMA). As Groundwater Sustainability Agencies (GSAs) work to comply with SGMA requirements and timelines, On-Farm Floodwater Capture and Recharge (OFFCR) is being studied to help increase recharge capacity. We implemented an OFFCR test on an organic almond orchard in the CV to assess achievable recharge rates attained through over-irrigation, and potential soil and water quality impacts. Irrigation water was applied via flood irrigation. We developed study sites and installed soil sensors for moisture and salinitymonitoring, took post-irrigation deep cores to assess changes in soil and porewater nitrogen and salt concentrations through the vadose zone, and monitored agronomic practices, recharge loading and crop yields.These studies were conducted on three recharge treatments with three replicated stations for each: 1) Control at about 6 inches of flooded water to meet ET as typical for irrigation (Control treatment), 2) Low Flooding of about 12 inches per irrigation application (Mid treatment), and 3) High Flooding of about 24 inches per irrigation application (High treatment).
  • Technical report: Modeling nitrate leaching risk from specialty crop fields during on-farm managed floodwater recharge in the Kings Groundwater Basin and the potential for its management

    Bachand, P.A.M.; Bachand, S.M.; Waterhouse, H.; Rath, J.; Ung, M.; Roy, S.; Kretsinger, V.; Dalgish, B.; Horwath, W.; Dahlke, H.; et al. (Sustainable Conservation, 2017-07-31)
    This project has focused on better understanding the potential impact of On-Farm Flood Capture and Recharge (OFFCR) on groundwater quality pertaining to salts and nitrate and on assessing potential management opportunities. To achieve these goals, we used a combination of field and modeling studies. For the field study, soil cores were taken to a depth of 30 feet in replicate across fields with three different specialty crops identified as important to the San Joaquin Valley (tomatoes, almonds, vineyards) and with potential suitability for OFFCR. A prime goal of the field study was to provide data for parameterizing two models developed to assess nitrate, salt and water transport through the vadose zone, prior to percolating into the groundwater aquifer.However, the field study also resulted in key findings that show its value as a stand-alone study: 1) Nitrate concentrations are highest in the upper vadose zone and affected by texture. Those effects are not evident in the deeper vadose zone. 2) Vadose zone nitrate concentrations are affected by the crop grown. These results suggest an opportunity for lower legacy mass transport for grapes and higher legacy mass transport for both tomatoes and almonds.3) Variability in individual farmers’ past and present fertilizer and water management practices contributes to different legacy salt and nitrate loads in the vadose zone.Data from the field study and other related and concurrent OFFCR field efforts were used during model development. The overall modeling approach was designed to model nitrate and salt transport for lands under OFFCR operation for different crop types, vadose zone characteristics and groundwater characteristics. The defined goals of this design and modeling approach were to: 1) model nitrate and salt movement through the vadose zone and into groundwater; 2) test the model against scenarios that consider different recharge rates, cultural practices, soil types, and depths to groundwater, assessing the timing and magnitude of loading through the vadose zone and the effects on underlying groundwater; and 3) recommend management practices to mitigate potential groundwater impacts. To achieve these goals, two models were integrated to simulate nitrate and salt transport through the vadose zone to groundwater under different scenarios: a 1D Hydrus model and an analytical groundwater model (AGM).
  • 2017 OFR demonstration site monitoring and analyses: Effects on soil hydrology and salinity, and potential implications on soil oxygen

    Bachand, S.M.; Hossner, R.; Bachand, P.A.M. (Sustainable Conservation, 2019-01-28)
    On-farm recharge (OFR) is a practice that uses surface water to alleviate demand on and replenish groundwater supplies. It can take on two forms: in lieu recharge and direct recharge. In lieu recharge utilizes surface water supplies instead of groundwater to irrigate crops. Direct recharge applies water beyond the needs of the crop and replenishes the groundwater supply. ...The present study examined OFR with grapes, walnuts, and pistachios at six sites in the San Joaquin Valley, plus one additional site from a previous study, also in the San Joaquin Valley. Each site was comprised of a recharge plot that received direct recharge paired with a control plot with the same crop and soil characteristics, but meant to receive in lieu recharge (via the flood system) or drip application with groundwater. At the end of the 2017 recharge demonstration, however, three control plots had also received direct recharge from water applications that exceeded the crop’s water demand. At another site, both control and test plots had only received in lieu recharge due to limited surface water amounts or the host growers’ more conservative volume of water application. ...The present study only covers one season of recharge. Long-term effects of recharge are not described by the present study and will require further monitoring. Further study is needed of the dynamics of soil oxygen during and after recharge events. Similarly, the fate of the water after it infiltrates past the root zone is not always known and the rate at which recharged water will reach an aquifer is seldom known for deep aquifers. A method to predict the fate of water quickly and broadly would be quite helpful in developing an on-farm recharge strategy. The present study does not look at the effects of recharge on soil biological processes, such as microbial respiration and plant oxygen demand. Further study of the recharge tolerance of specific species and rootstocks, as well as the impact on plant disease, is crucial.

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