8/7/2012 DESIGN REVIEW COMMITTEE Minutes

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A Mashpee Wampanoag Affordable Housing 183 Meetinghouse Road Plan Review Page two one test be conducted in each of the SWMA with the soil logs and infiltration rates as determined in the field to be shown on the plan prior to final approval. 3. The report (pp 5) suggests that only a portion of the rain garden Pond3 would be built at the time of road construction and that the remainder would be built once full build out of the project is complete. 4. This area is a relatively small portion of the full road construction. It would make more sense to do the full construction of Pond 3 while construction equipment is on site and doing similar work for the other areas. It would also eliminate disturbance of otherwise stabilized areas in the future. The added cost of constructing the full area at the beginning would be much less than having to mobilize equipment at a later date and to have to provide temporary measures for stormwater while the new area stabilizes. It is recommended that the full area of Pond 3 be constructed. 5. Is it the intent of the design to clear cut each of the SWMA that are in natural depressions to the tree lines shown on the plans? If so, a note to that affect or a designation of the proposed tree line should be provided. 6. All of the pipe size calculations were done for a 10 year storm. The calculation should be done for the 25 year storm as required by Section IX(J)(6) of the regulations. 7. The pipe detail tabulation provided at the end of the report shows the invert elevations for pipe flow entering and leaving structures. In each case the invert elevations of the flow out is higher than the invert elevations for flow in. Please explain. Customary practice is to have the elevations for pipe inverts out at least 0.10 feet below the invert in. 8. Exfiltration rates have been indicated based on soil type and the Rawls method for drawdown time in the SWMA. This assumes that the appropriate soil conditions occur where the leaching pit wicks are located. If other conditions exist, the analysis will not be correct. Soil investigation in each of the SWMA should be done to confirm the analysis provided. This is especially true in the deep depressions where the SWMA are located as soil formations could be different there than in the higher elevations. 9. The TSS removal sheet should show that at least 80% TSS removal is obtained for each system. Ladder Tower Turning Radius Plan For most situations the turning radius information shown on the plans indicates that there will not be interference for maneuvering. However, the outside line of travel for the platform extends over the sidewalk area shown around the main cul-de-sac at the end of the double roadway. If any improvements such as light poles or trees are within this line of travel they could be a hindrance to safe maneuvering of the apparatus. Sufficient clearance for such items should be allowed for. Roadway Construction Plans General Comment: All of the plans call for the use of reinforced cement concrete drainage pipe which is more than acceptable. Was any consideration given to the use of ADS pipe? The latter is easier to lay and installation is quicker. It is also acceptable for use in standard drainage facilities such as the proposed project. Sheet 2 of 12: 1. Dimensions should be provided for SWMA#2 and #3. The full build out dimensions of SWMA #3 should be shown. 2. The discharge pipe at the end of the cul-de-sac on Road B ends at the top of a relatively steep slope. There is a potential for erosion of the 10 foot wide swale that is proposed for the slope.