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Adam Pescatore 3- 20 September 2018 Harvest-Lathrop Composting Facility San Joaquin County 10. Geomembrane Seam Testing (Non-Destructive and Destructive). Non-destructive and destructive geomembrane seam testing is standard industry practice and should be observed especially due to the detention pond liner design that does not limit hydraulic head on the geomembrane liner and due to shallow groundwater i.e., less than 5-foot separation that exists at the Site. On 28 August 2018, Central Valley Water Board staff in an email provided examples found on the internet of construction specifications for non-destructive and destructive seam testing. 11. Leak Location Survey. Neither the Specifications or the CQA Plan contain provisions requiring that an electric leak location survey be performed on the geomembrane liner following completion of construction. This is required since the liner design does not limit hydraulic head on the geomembrane liner and due to shallow groundwater i.e., less than 5-foot separation that exists at the Site. 12. Pan Lysimeter Sampling.The Pan Lysimeter Detail on the Plans (sheet 3 of 7) shows the pan lysimeter monitoring tube with fittings that may make it difficult to monitor and obtain samples from the pan Lysimeter. The monitoring tube must allow the Discharger to obtain samples for laboratory testing to determine if a leak has occurred. What monitoring/sam piing device does the Discharger plan to use for the construction configuration shown in the plans? 13. Location of 4 piezometers to be installed.The Plans indicate that four piezometers will be installed but on (sheet 2 of 7)the location of only three piezometers (Construction Note and balloon 8) are shown. 14. Two pan lysimeters per detention pond.The Plans show two pan lysimeters per detention pond even though the notes indicate that each pond will only have one pan lysimeter installed. 16. Cross-Section details are Incorrect. Cross section views B-B and C-C on Plans sheets 4 and 5 of 7 do not correspond to the cross sections taken on sheet 2 of 7. The horizontal scale for the cross sections is not correct i.e., not 1" = 1'. Furthermore, the cross sections of the detention ponds should indicate that there is a GCL liner below geomembrane and above the compacted subgrade. Cross section C-C on sheet 5 of 7 shows the 18" PVC pipe well below the finish grade which is not consistent with the site improvement plan sheet 2 of 7. 16. Pond Bottom with Zero Slope.The detention ponds do not have any base slope which may cause"whaling" of the geomembrane liner if leakage through the liner were to occur and gas from decomposition from waste were to form below the liner. Natural Resources Conservation Service (NRCS) Code 521 recommends a bottom slope of one percent and venting underneath the pond where the"invert elevation of the pond is within 2 feet of the seasonal high water table. Hydrostatic pressures from fluctuating groundwater levels or leakage through the liner may cause the liner to float." Furthermore,the plans and specifications should provide details for any permanent ballast that may be required to prevent wind uplift of geomembrane. 17. No Units in Table 2 of Soil CQA Plan.Table 2 of the Soil CQA Plan does not state the units for testing frequency. 18. Subgrade Suitability.The Discharger submitted a Pavement Design Report dated 17 August 2018 which assumed an R-Value of 50 for the native subgrade. The Discharger's Specifications or Soil CQA Plan should provide testing to verify the assumption made.