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Rule 4.05 and 4.10.3 —Hydrolo2ic Balance and Water Control Measures Hydrology for RP-A and Pond (Illustration 59) 3. The Division somewhat disagrees with the statement by Blue Mountain Energy (BME)regarding the purpose of riser pipes. Another reason to use riser pipes is to limit the amount of sediment that is transported into the outlet(aka spillway) and downstream to the receiving water. We suggest that BME reconsider the design of the primary spillway. Alternatively, please provide supporting information to show that your outlet design will not become plugged. The actual mechanism that limits the amount of sediment transported to the downstream receiving water is the slow velocity in the pond. Risers have their place, but are not required. The goal of the sediment pond is to reduce the settleable solids concentration during the 10 year storm to below 0.5 ml/l, which this pond does without a riser. A note specifying flared end sections with sloped trash racks has been added to the outlet on Map 162A. 12. Several channels on Map 162 take nearly 180-degree turns, therefore baffles or other energy dissipation structures may be needed at these locations. Blue Mountain Energy should add a discussion of these structures (and possibly figures) to the design. Many channels on the refuse pile terraces do have obtuse junctions with other channels. What will happen as the channel on the higher terrace approaches the continuous channel on the lower terrace, the outside bank will diminish to the point that water will start to spill down to the lower terrace down a steeper slope. The slope will be a maximum of 3:1 and the maximum height should be about 3 feet. This area subject to shallow but steep flow will need to be protected from erosion. The only way to model this hydraulic scenario is with extremely expensive computational fluid dynamics software or a physical scale model. Without these tools at our disposal, we planned to observe the performance of the first transition area developed as the refuse pile mounted and develop a plan to protect the transition areas from erosion. Alternatively, we have made some worse case assumptions and applied them to the affected areas. A typical detail and rip rap chart have been added to Map 162. Calculations are in Illustration 59 Appendix E. It is the author's opinion that the rip rap is oversized because the steep section will not see the full flow depth assumed. We will build the first one as we get to it, do some experimenting, and reevaluate. 13. It appears that there are errors in the Structure Routing Details tables in the SEDCAD output(one table for each return event). Please address the following and check all others for accuracy. a. There is no Structure 92 in the tables. There is essentially no lag due to routing from structure 2 to structure 1. Structure 2 is basically within structure 1. For some reason, SEDCAD doesn't display it if the Muskingum K and X are zero. Very minimal values have been added so that it shows up in the table.