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t Sam Monaco -4- 9 June 2017 Harvest-Lathrop Composting Facility of the windrow area discharging to pond B where operational use amounts to 0.01 inches of wastewater over 268,330 ft2 of area. e) Dust Control. The Discharger's water balance dated 10 April 2017 proposes using detention pond wastewater for dust control 21 days per month during wet season months. In December through February where the wettest year monthly precipitation (column 1) exceeds the average adjusted pan evaporation (column 6), the assertion that wastewater could be used for dust control for a majority of those months is not plausible. Furthermore, as stated in the groundwater separation item below, in the 2016-2017 wet season during the months of December, January, and February the number of days where reported rainfall was equal to or greater than 0.01 inches was 10, 17, and 16 days respectively. The need for dust control during these months for ponds designed to contain waste in the wettest season is essentially non-existent. f) Omission of including 25-year 24-hr storm in monthly water balance calculations. The General Order All Tiers Specifications#6 requires that detention ponds contain without overflow or overtopping "all runoff from the working surfaces in addition to precipitation that falls into the detention pond from a 25-year, 24-hour peak storm at a minimum." The Discharger's water balance for pond A and pond B does not include the storage volume capacity necessary to contain a 25-year, 24-hour peak storm event falling into the detention ponds. 4. Insufficient Compost working surface slope of 0.25% to 0.50%. The Discharger's proposed working surface slopes do not comply with General Order Design, Construction and Operation Requirements-All Tiers (All Tiers Specifications) specification #1. The Discharger's Final Technical Report proposes to grade its compost area working surfaces towards detention pond A at 0.25% over a distance of approximately 900 feet. The Discharger states that drainage will rely on sheet flows towards the detention pond since "surface-water conveyance systems, such as, drainage ditches or area drains with drop inlets do not exist at the site, and are not feasible to be utilized due to shallow depth to groundwater and relatively flat grades at the site." Additionally, the Discharger proposes to grade its compost area working surfaces towards detention pond B at 0.50% over a distance of approximately 500 feet where sheet flow must cross a five inch thick by 50-foot wide asphalt concrete road, and 450-feet of six inch thick Class 11 aggregate base. The depth of the asphalt concrete will prevent drainage of the working surface sloping towards pond B. The proposed slopes will not minimize ponding and in turn will not reduce infiltration of liquids. 5. Inappropriate reliance on sheet flow for leachate conveyance. The General Order All Tiers Specifications #1.b requires that composting areas "reliably transmit free liquids" to a containment structure "to minimize the potential for waste constituents to enter groundwater or surface water." The proposed design to rely on sheet flow over long distances (i.e. 450 and 900 feet) does not meet the requirement of the General Order specification. 6. Composting working surfaces not designed for year round equipment access. The Discharger proposes working surfaces consisting of onsite compacted soils with a minimum thickness of one foot which seemingly meets the requirements of General Order Design, Construction and Operation Requirements-Tier II Only (Tier II Specifications) specification #1. However, the working surface must also meet the All Tiers Specifications #2 which