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Mr. Clapper and Mr. Romig <br /> September 24, 1996 <br /> Page 5 <br /> south side of the reservoir parallel to the Chalk Mountain Intercepter. At a point just to the <br /> east of where the Intercepter drops down from the upper ditch, the pipeline would leave <br /> the road and traverse the hillside up to the upper Chalk Mountain Intercepter access road. <br /> The pipeline would then follow the access road to the existing Robinson Reservoir turnout <br /> from the Intercepter. At this point, the proposed pipeline would discharge into Robinson <br /> Reservoir. The overall pipeline length would be approximately 5,040 feet. <br /> The pipeline would be installed with a minimum cover of 2.5 feet to protect it from <br /> the vehicle loads along the roadway, and would be bedded in pea gravel through the <br /> majority of its length (ref. dwg. D4-2.04). Due to the shallow bedrock along the pipeline <br /> route, It would be difficult to bury the pipeline deep enough to prevent freezing. For this <br /> reason, the pipeline was designed with a continuous positive slope so that the pipeline <br /> would drain when the pumps are not operating. In order to maintain the positive slope, it <br /> will be necessary to excavate a trench through the Dam 4 embankment that will be about <br /> 8 to 10 feet deep (ref. dwg. 134-2-01). Since the pipeline will be installed below the <br /> normal high water level In the reservoir, the pipeline must be bedded in fill material which <br /> masts the embankment Zone 1 specifications and cutoff collars will be required (ref. dwg. <br /> D4-2-04). State Engineer approval will be required for the section of the pipeline within <br /> the embankment and emergency spillway. The pipeline crosses Robinson Dam along the <br /> south abutment. We have specified that the pipeline invert elevation at this location be at <br /> or above the normal high water level in the reservoir. Also, we have specified that the pipe <br /> be bedded in select fill and three HDPE waterstops be installed in the pipeline. This <br /> crossing should not require State Engineer review or approval. The volume of water which <br /> will drain back to the seepwater pond when the pumps shut down will be about 11,300 <br /> gallons. The pipeline route described above is expected to involve minimal rock <br /> excavation. <br /> A PVC liner Is shown In the pipe trench which will envelope the gravel bedding to <br /> provide a secondary containment system for the pipeline. A single layer of filter fabric Is <br /> 90' d Z00' uN 2b: TT 96 bZ daS Z08Z-T9Z-�H-T : �31 3oSSd 'g Ja( aaym - m• m <br />