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City of Davis Constructed Wetland Performance Evaluation

wastewater plant tissue sampling soil sampling Salinity & Nutrients

Land IQ conducted a performance evaluation of constructed wetlands, known as overland flow cells, to provide recommendations on optimizing nutrient removal as part of a wastewater treatment process. The evaluation included collecting and interpreting analytical data from plant tissue and soil samples within the overland flow cells and in control areas, as well as observing site conditions. To provide recommendations to the City of Davis for improving site performance, Land IQ considered grass varieties, managing for optimum yield, managing grass clippings from mowing, irrigating for optimum performance, and monitoring. The overland flow cells provide secondary treatment for the wastewater collected, treated and discharged by the City of Davis wastewater pollution control plant.

City of Davis Manganese Study

soil analysis waste discharge permit wastewater Agriculture Water Resources Salinity & Nutrients

Land IQ conducted a study to determine the relationship between site-specific manganese levels in irrigation water and agricultural soils. The investigation included sampling a range of soil types, and interpreting results from soil analysis to determine the relationship between manganese and soil characteristics such as pH, texture, and other nutrient interactions. This information was used to fulfill the requirements of the discharge permit under which the City of Davis discharges treated wastewater into Willow Slough and the Yolo bypass. The wastewater treatment plant operated by the City of Davis in Davis, CA, collects wastewater from residents of Davis, California and two unincorporated areas in Yolo County.

Incirlik Air Force Base Water Reuse and Conservation

wastewater wastewater recycling water conservation Water Resources

Land IQ provided technical expertise and project management to the Air Force Center for Engineering and the Environment (AFCEE) and the United States Air Force for a reuse feasibility assessment and design located at the Incirlik Air Force Base outside of Adana, Turkey. The assessment and design focused on using conventionally treated wastewater to irrigate various turf and landscaped areas on the base. This project was stimulated by the need to conserve on-base water supplies at the Incirlik Base both from a water conservation perspective and for security purposes.

The feasibility study evaluated the science- and design-based needs associated with the conversion of some on-base irrigation water sources from potable water to treated wastewater. This project successfully reduced reliance on off-base water supplies through irrigation with treated wastewater and other conservation practices associated with landscape irrigation. The use-efficiency was maximized in this project because water storage was limited. A nutrient and hydraulic management plan was constructed to ensure that no over-application of nutrients or recycled water occurs.

Santa Clara River Watershed Agricultural Irrigation Thresholds/TMDL

chloride agriculture salinity wastewater water management Agriculture Water Resources Salinity & Nutrients

Land IQ personnel worked with Los Angeles County Sanitation Districts to serve as the lead technical consultant for the Santa Clara River Watershed TMDL Collaborative Process. Land IQ specifically focused on the agricultural irrigation thresholds for chloride and salinity for the production of avocados, strawberries and nursery crops. This work involved collaboration in stakeholder meetings with representatives from:

  • California Avocado Commission
  • California Strawberry Commission
  • Nursery Crop Organizations
  • Individual Growers
  • Ventura County Farm Bureau
  • California Regional Water Quality Control Board
  • Newhall Land and Ranch Company
  • United Water Conservation District
  • Elected Public Officials
  • Various Environmental Groups

Over a 2.5-year period, a detailed literature review and evaluation was developed to help determine the potential threshold of irrigation water quality constituents of concern, specifically chloride and salinity, on sensitive crops as a basis of the TMDL process. Local grower input was gathered through interviews and field surveys. To establish acceptable irrigation water quality, NewFields conducted a detailed assessment of water quality, irrigation practices, cultural practices and drainage management. The work also included comprehensive public notification efforts with stakeholder groups, public officials, researchers, and farm managers. A six-person academic technical panel comprised of experts in this field reviewed all work produced by NewFields. This work has been highly influential in establishing a chloride TMDL for irrigation of sensitive species in the Santa Clara River Basin. Despite the controversial subject matter, the literature review and findings were commended by industry professionals, agencies, environmentalists, and academics on both sides for scientific merit and objectivity.