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Page 4, June 13, 2007 Rule 4.05.3(2) Temporary diversions shall be constructed to pass safely the peak runoff from a precipitation event with a 2 year, recurrence interval, or a larger event as specified by the Division for good cause shown. The structure is a temporary diversion. The application is in compliance with this rule. The project was designed to handle flows from a 10-yeaz 24-hour storm event (see Table 44E) and any flows from the overflow of a fresh water storage pond. Rule 4.05.3(4) Diversions shall be designed, constructed, and maintained in a manner which prevents additional contributions of suspended solids to streamflow and to runoff outside the permit area, to the extent possible using the best technology currently available. Appropriate sediment control measures for these diversions may include, but not be limited to, maintenance of appropriate gradients, channel lining, revegetation, roughness structures, and detention basins. The application is in compliance with this rule. The proposed culvert is a channel lining. The project includes a basin (concrete vault for pipe size and grade transition). Rule 4.05.3(5) When constructed, diversions shall be designed and located in a manner that minimizes the potential for landslides. No diversion shall be constructed on existing landslides, unless approved by the Division. The application is in compliance with this rule. The culvert and concrete vault aze designed and located to minimize the potential for landslides. The project is maintenance as a result of a land slump, and is proposed to arrest the slide. By approval of the technical revision, the Division approves this maintenance construction on an existing landslide. Rule 4.05.3(7) Diversion design shall incorporate the following: Rule 4.05.3(7)(a) Channel linings, including channel riprap, shall be designed using standard engineering practices to pass safely the design velocities. The application is in compliance with this rule. The culvert and concrete vault are considered channel linings. They were designed using standard engineering practices to pass safely the design velocities and quantities. Rule 4.05.3(7)(b) Freeboard shall be no less than 0.3 feet. Protection shall be provided for transition of flows and for critical areas such as swales and curves. Where the area protected is a critical area as determined by the Division, the design freeboard may be increased. The application is in compliance with this rule. The structure is not an open ditch. The vault provides for transition of flows in the critical area of changing grades.