EASTERN MUNICIPAL WATER DISTRICT San Jacinto Groundwater Basin Numerical Flow Model Update Brian Powell Director of Planning March 17,

Background - Regional Groundwater Model 2 The District uses its regional groundwater model to simulate groundwater flow through each sub- basin and is used to predict groundwater levels for a variety of recharge and pumping conditions The District last updated its regional model over 12 years ago, since then there has been: o A significant amount of information collected o A large change to groundwater levels o An increased understanding of the basins

Regional Groundwater Model 3 The regional groundwater model helps the District meet regulatory requirements, supports the District’s groundwater rights, and provides technical input for District projects such as: Indirect Potable Reuse Local Groundwater Banking Desalter System Expansion Moreno Valley Groundwater Development Water Rights in Perris Valley

Status of Project 4 Significant progress has been made on the development of the updated model: Conceptual model update is complete Steady state (static) calibration is complete Transient (dynamic) calibration is underway (Transient calibration for the Intake Area has been submitted for review by staff) ft / MSL = feet above Mean Sea Level AF = Acre-Feet

Advisory Panel 5 An Advisory Panel (AP) was selected from various regulatory and grant funding agencies to provide peer review of the project. Panelists include representatives from: o United States Geological Survey (USGS) o California Department of Water Resources (DWR) o Santa Ana Regional Water Quality Control Board o Local Groundwater Expert An additional participant in the review process is the advisor to the Hemet-San Jacinto Watermaster, a stakeholder in this project

Consultant Selection Process 6 A request for proposals (RFP) was developed and eight qualified engineering firms were invited to propose The District received proposals from four firms RMC’s proposal was rated highest by the selection committee

Original Cost Estimate 7 The RFP developed represented the level of work required as known at the time Out of 4 submitted proposals, 3 were within 3% in terms of cost (including RMC’s proposal)

Basis for Amendment 8 Changes to the scope of work were recommended by the Advisory Panel and considered improvements to the final product by staff Consultant submitted a contract amendment request in February 2015 to cover their added costs The most significant changes to the scope of work include the following three areas:

Change in Scope Number Highly engaged Advisory Panel (AP) requiring: Additional submittals/responses by consultant on technical modeling issues Additional project meetings and conference calls to support and resolve technical inquiries Additional review and interaction to gain acceptance by AP members Value: A groundwater model that has undergone technical scrutiny by regulatory and funding agencies gaining their acceptance through the process

Change in Scope Number Requirement: Updated land use to account for historic changes from undeveloped/agriculture to developed lands Action: Integrated historical land use tracked by the District Result: Changes to recharge (percolation) rates over the model calibration period Value: Provides for a better representation of rain fall and irrigation return flows to the basin

Change in Scope Number Requirement: Inclusion of recent report and testing results Action: Update model to include technical results from IRRP monitoring well installation, Well 93 installation, Moreno Valley drilling, water rights estimations, and Salt Creek storm water flows Result: Improved transient calibration throughout the Basin Value: Provides a better understanding of the Basin and potential for groundwater production

Next Steps 12 Complete review of Intake- area model for IPR Complete overall transient calibration of the basin-wide model Advisory Panel meeting on 3/31 to review calibration progress to-date Select and set up scenario runs (predictive modeling)

Schedule 13

Recommendations 14 Staff recommends: Approval of the Consultant Amendment Request #2 for $146,013 increasing the total contract to $505,215 Appropriation of an additional $252,355 for a total Project cost of $730,555

Contact Information EASTERN MUNICIPAL WATER DISTRICT Brian Powell Director of Planning x