March 18, 2016 Danielle Moss & Laura Foglia Omochumne-Hartnell Water District & Sloughhouse Resource Conservation District Basin Boundary Modification Request March 18, 2016 Danielle Moss & Laura Foglia

Overview Proposed Basin Boundary Submittal Requirements Regional History & Management Effects of Modification on Sustainable Management Hydrogeology Scientific Information

Sustainable Groundwater Management Act (2014) Emergency regulations to establish a process for local agencies to request changes to existing basin boundaries Governing Criteria likelihood that the proposed basin can be sustainably managed whether the proposed basin would limit the sustainable management of adjacent basins whether there is a history of sustainable management of groundwater levels in the proposed basin

Request Requirements Demonstrate proposed basin can be sustainably managed Notice and consultation with interested local agencies and public water systems in the affected basins Technical information on boundaries and conditions in the proposed basin

Proposed Basin Boundary

Regional History 1997 OHWD, Galt Irrigation District, & Clay Water District JPA & Coordinated GMP 2000 Water Forum Agreement 2002 Southeast Sacramento County Agricultural Water Authority GMP 2004 Sacramento County Water Agency GMP 2006 Central Sacramento County GMP 2011 Draft South Basin GMP 2002 SSCAWA GMP

Regional History 1997 OHWD, Galt Irrigation District, & Clay Water District JPA & Coordinated GMP 2000 Water Forum Agreement 2002 Southeast Sacramento County Agricultural Water Authority GMP 2004 Sacramento County Water Agency GMP 2006 Central Sacramento County GMP 2011 Draft South Basin GMP 2006 Central Sacramento GMP

Management History Flashboard Dams Four flashboard dams to facilitate increased groundwater recharge Cosumnes River Flow Augmentation Project Supplemental flow into Cosumnes from Folsom South Canal to induce groundwater recharge Cosumnes Floodplain Groundwater Recharge and Banking Project Conjunctive use of surface water onto recharge basins Cosumnes River Flow Monitoring Streamflow monitoring for lower Cosumnes River Cosumnes River Task Force

Effects of Boundary Change on Sustainable Management in Cosumnes Subbasin Prevents public agencies from being split between GW subbasins Promotes local control and leadership

Effects of Boundary Change on Sustainable Management in Cosumnes Subbasin Decreases isolation of areas with limited resources Aligns well with watershed boundary and San Joaquin - Sacramento Valley boundary for integrated surface water & groundwater management

Effects of Boundary Change on Sustainable Management in Cosumnes Subbasin Affected region land use better aligns with Cosumnes subbasins Sacramento County General Plan 2005 - 2030

Causes certain public agencies to be split Effect of Boundary Change on Sustainable Management in South American Subbasin Probably doesn’t decrease likelihood of developing Groundwater Sustainability Plan Causes certain public agencies to be split Sacramento County Water Agency Requires modification to existing Central Sacramento GMP water balance Some modification regardless of basin boundary change

Effect of Boundary Change on Existing State Programs CASGEM Agencies in Central Basin currently monitor over OHWD South Sacramento Basin has contracted with consultant for development of CASGEM in remaining areas GMPs Existing GMPs will need modification SGMA Establish Groundwater Sustainability Agencies Basin-wide Groundwater Sustainability Plans

Hydrogeology Flow (Q) is proportional to: Head gradient Area through which the water is flowing (cross-sectional area) Permeability of material (hydraulic conductivity) depends on the medium (pore size, pore density) Porosity – depends on sorting of grains (not grain size), packing, degree of cementation, degree of fracturing Driving force = head gradient, slope of potentiometric surface

Hydrogeology Unconfined – water table in contact with atmosphere. Confined – potentiometric (pressure head) surface rises above top of aquifer due to overlying confining unit. Confining unit – low permeability unit between aquifers can restrict flow and provide leakage.

Groundwater flow GW in continuous slow movement from recharge areas (usually upland areas) discharge areas (springs, baseflow, wetlands and coastal zones)

Scientific Information Geology of the Cosumnes & South American Subbasins 2006 Central Sacramento GMP

Scientific Information Well data gathered, river/aquifer interaction and conceptual model

Scientific Information General flow direction in the Cosumnes basin

Scientific Information Groundwater contours

UCD studies: effects of aquifer heterogeneity FALL Preferential flow paths under the river channel Areas where river and aquifer are “reconnecting” in the spring Importance of considering heterogeneity SPRING Fleckenstein et al., 2006

Scientific Information: groundwater levels near the Cosumnes

Scientific Information: hydrological cross-sections

Scientific Information

Scientific Information

Scientific information: electrotelluric survey method Passive geophysical technique to evaluate presence, depth, thickness, and associated fluids such as water or hydrocarbons in geologic formation in the subsurface Derived measuring the effects that telluric currents have on the earth’s electric field at the surface Results are currently in draft

Scientific information Comparison between geophysical and hydrological cross-sections  results currently in draft

Questions?