SBWQM (South Bay Water Quality Model)

Criterion	Explanation
Model name/version	SBWQM (South Bay Water Quality Model)
General Description	Water quality economic model for South Bay Region of California. Costs are estimated based on delivery sources (State Water Project, Central Valley Project) and water salinity for residential use.
Model Domain	Bay Area region from Contra Costa County in the North to Santa Clara County in the South
Developer	United States Bureau of Reclamation, CH2M Hill
Hardware computing requirements	Not specified.
Code language	No coding performed, calculations were executed in Microsoft Excel.
Original application	Original model developed to evaluate economics of Los Vaqueros Reservoir expansion. The origin of this model is likely related to the Salinity Economic Impact Model (SEIM) and the Lower Colorado River Basin Salinity Economic Impact Model being developed by the United States Bureau of Reclamation (Colorado River Basin Salinity Control Forum, 2017). No confirmation of model interconnectedness could be obtained from various sources contacted.
Public/proprietary and cost	No information could be gathered about rights and permissions.
Physically or empirically based	Model empirically based on relationships developed from measured water quality cost data.
Mathematical methods used	Key equations and relationships were obtained from model used by the Metropolitan Water District of Southern California to estimate water costs (direct communication with Lucas Bair, United States Geological Survey). Model uses estimated relationships between salinity and damages to residential appliances and fixtures to determine benefits from changes in salinity. Costs from salinity management are a function of volume and initial salinity of diverted water from the South Bay Aqueduct or the Contra Costa Water District.
Input data requirements	Number of affected households, characteristics of households in the South Bay region, water quality (chloride concentration in mg/L), water supply source, life-span of residential fixtures and appliances. Data can be obtained from public sources or from water districts.
Outputs	Model outputs compare changes in average salinity and changes in annual salinity costs. Outputs include residential salinity costs, changes in annual monetary benefits and long-term average electrical conductivity; output given in three distinct development levels (years 2025, 2055, 2085).
Pre-processing and post-processing tools	Excel spreadsheet of model.
Representation of uncertainty	Uncertainty not directly incorporated into model framework.
Prevalence	Not common; mainly used by California water districts. Used by United States Bureau of Reclamation for estimating water quality cost for the South San Francisco Bay Area region.
Ease of use for public entities	No public source of model easily obtainable. Model easy to use once Excel spreadsheet is obtained.
Ease of obtaining information and availability of technical support	No commercial help desk available, no internet user forums found. Information availability limited to communication with individual modelers.
Model and Source code availability	No source code, model is Excel based. Model spreadsheet can be obtained from the United States Bureau of Reclamation upon request from https://www.usbr.gov/mp/ssjbasinstudy/contact.html.
Status of model development	Updates in 2013 allows model to use CalLite outputs in replacement of CALSIM II outputs and to include various socioeconomic scenarios (CH2M Hill, 2013). Future update status of model is unclear.
Challenges for integration	Model output only available for specific development levels (years 2025, 2055, 2085), model not compatible with other models requiring smaller output timesteps.

References

Bair, L. and MacEwan, D. 2013. Central Valley Project Integrated Resource Plan: Economics Performance Assessment Tools. Prepared by CHM2 Hill.

CH2M Hill. 2013. Development and application of other performance assessment tools. Available at http://www.cwemf.org/AMPresentations/2013/OtherCVP-IRPModelingTools.pdf (accessed 19 October 2018).

Colorado River Basin Salinity Control Forum. 2017 Review Water Quality Standards for Salinity Colorado River System. Available at http://www.coloradoriversalinity.org/docs/2017%20Review%20-%20June%20Draft.pdf (Accessed 26 October 2018).

USBR (United States Bureau of Reclamation). 2016. Central Valley Project Integrated Resource Plan. Available at https://www.usbr.gov/mp/ssjbasinstudy/docs.html (accessed 19 October 2018).

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