1. 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

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

3. 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

4. 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

5. Proposed Basin Boundary

6. 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

7. 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

8. 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

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

10. 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

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

12. 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

13. 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

14. 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

15. 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.

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

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

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

20. Scientific Information
General flow direction in the Cosumnes basin

21. Scientific Information
Groundwater contours

22. 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

23. Scientific Information: groundwater levels near the Cosumnes

24. Scientific Information: hydrological cross-sections

25. Scientific Information

26. Scientific Information

27. 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

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

29. Questions?