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Based on the following assumptions, the 100-year flood elevation for the northwest portion of Weber Pond (6.5 acres) is 976.5 and for the southeast portion of Weber Pond (1.0 acre) is 975.5: The collapsed outlet from the northwest portion of the pond was equivalent to a 24-inch corrugated metal pipe at Elevation 973.7, 2. Future (full) development conditions in the watershed. 3. Pre -development Echo Lake overflow conditions (996.6 overflow). 4. Normal water level for southeast portion of Weber Pond at 973.4 and ditch outlet elevation at 973.7. At its flood elevation of 9765, Weber Pond will inundate 60th Street North. However, since the City of Mahtomedi will be realigning 60th Street North, VBWD does not anticipate taking measures to reduce the flood elevation, All available flood storage is needed at Weber Pond in conjunction with additional storage on Echo Lake to reduce flood elevations on Long Lake. Realigned 60th Street will be located north of the existing street and become the east - west through street for the area. 4.2.4.3 VBWD Water Quantity Management Goals Because development is occurring in the Weber Pond watershed, replacement of the 24- inch temporary outlet is a high priority. The size of the replacement outlet from the northern portion of Weber Pond is proposed to be smaller than the existing outlet. Based on VBWD's analysis, a new outlet from the northwest part of Weber Pond is proposed to be a 9-inch diameter orifice, and the outlet from the southeast part of the pond will not be altered. Because the outflow from Echo Lake will also be reduced, the 100-year flood elevation of the northwest portion of Weber Pond will be unchanged as a result of the new outlet construction. Since the flood elevation is not altered, no permanent easements need to be acquired. VBWD anticipates combining this project with the Echo Lake outlet project (see Echo Lake Water Management Plan section). Also, VBWD must obtain permission from the DNR to install a new Weber Pond outlet. 4.2.4.4 Water Oualitv and Public Use Dat No water quality data for this pond have been collected by VBWD, the City of Mahtomedi or private citizens. The pond provides aesthetic views, stormwater detention and runoff water quality treatment. The old streetcar grade provides a trail between the two sections of the pond. In the past, the DNR occasionally used Weber Pond for fish rearing purposes. 4.2.4.5 VBWD Water Oualitv Management Goals Based on its existing and desired recreational use, Weber Pond is classified as a Category V water body (wetland) in Section 3.2 — Water Quality Management Plan. Further description of this classification can be found in Section 3.2. Because the current water quality of Weber Pond appears to be consistent with its recreational usage, future management efforts will focus on preservation of the existing water quality. Section 3.2 shows the management action to be not determined because of the lack of 23\82\045\SEC4.RPT\KMH 11 DRAFT: June 23, 1994