The Stockton metropolitan area flood control levee improvements were designed and constructed by the San Joaquin Area Flood Control Agency (SJAFCA) in the late 1990’s, and were certified by the United States Army Corps of Engineers (USACE) in 2000 as providing protection against the 100-year base flood. However, USACE recently informed SJAFCA that the levee certifications are no longer valid per EC 1110-2-6067. To retain FEMA accreditation, these levees must be re-evaluated to show compliance with FEMA criteria identified in 44CFR 65.10.
The levees (56 miles total) to be certified are:
- Bear Creek System — Bear Creek , Pixley Slough, Bear Creek Wing levee, Paddy Creek, Mosher Diversion, Upper Mosher Creek (36 miles total)
- Calaveras River System — Stockton Diverting Canal, Mormon Slough, Potter Creek and Upper Calaveras River (20 miles total)
Levee evaluation work consists of:
- Surveying and mapping - utilized LiDAR data, GIS aerial mapping and field surveys
- Hydraulic modeling, interior drainage and embankment protection analyses
- Geotechnical analyses - 74 cross-sections evaluated by DWR in the ULE/NULE investigations (each cross-section based on borings at levee crowns and landside levee toe), 10 additional cross-section models created for areas not covered by DWR investigation, 6 new borings to be performed to update DWR models that show potential seepage issues
- Closures and O&M Information review and update
- Preparation of certification packages to submit to FEMA
Levee certification packages were submitted to FEMA, Region IX on February 11, 2015.
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