Last updated on 06/11/2025
Seepage Management
Groundwater data help the SJRRP determine allowable flow rate releases. Here you will find real-time well data, weekly groundwater reports, monitoring well atlas, well construction updates, and documents related to the Seepage Management Plan (SMP).
Reclamations's Seepage Management Plan has two goals
- To limit or reduce Restoration Flows to the extent necessary to avoid material adverse groundwater seepage impacts, which are waterlogging or root zone salinity impacts to agricultural crops. We do this through over 200 groundwater monitoring wells, setting of groundwater level thresholds in these wells (see Appendix H of the Seepage Management Plan), and limiting Restoration Flows to avoid increasing groundwater levels over these thresholds (see Appendix J of the SMP).
- Construct seepage projects, which may include physical or non-physical projects, that allow higher flows in the San Joaquin River and bypasses without causing groundwater seepage impacts. Seepage projects may include seepage easements, land acquisition from willing sellers (see FAQ sheet below), interceptor lines, drainage ditches, slurry walls, etc. The map below shows seepage project priorities by the flow level that might impact the identified parcels.
Seepage Management Plan - September 2014 (Appendices E, H and J updated March—June 2017)
- Main Body of SMP
- Appendix A: Seepage Effects of Concern
- Appendix B: Historic Groundwater Levels and Surface Water Flow
- Appendix C: Areas Potentially Vulnerable to Seepage Effects
- Appendix D: Sediment Texture and Other Data (updated May 2015)
- Appendix E: Monitoring Network (updated March 2017)
- Appendix F: Aerial Imagery, Remote Sensing Data
- Appendix G: Soil Salinity Thresholds
- Appendix H: Groundwater Level Thresholds (updated March 2024)
- Appendix I: Groundwater Modeling
- Appendix J: Operations (updated March 2017)
- Appendix K: Landowner Claims Process
- Appendix L: Seepage Project Handbook
- Attachment A – Methodology
- Attachment B – Reclamation Final Design Process, April 2008
- Attachment C – Reclamation Design Data Collection Guidelines for Drains, Chapter 3, Section 8, September 2007
- Attachment D – Slurry Wall Cost Estimates, 2011
- Appendix M: References Cited