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in DeMontreville Highlands 3rd Addition (Pond 1), in the City of Lake Elmo. If overflow from Pond I occurred, water would flow to the stream which carries water from Long Lake to Lake DeMontreville. MNDOT's 1987 work on T.H. 36 included construction of a new bridge over the DNR Gateway Trail. As part of this work, MNDOT installed a 24-inch diameter culvert under the Gateway Trail to equalize Ponds A and B (see Figure 4-6). However, this culvert was to be blocked, in accordance with VBWD's request that flow be directed to Pond I. In 1993 VBWD found that the blocks were not installed. As a result, the overflow direction changed. After MNDOT's work, when water filled Ponds A and B, overflow would occur from the pond on the west side of the trail (Pond A) prior to overflow from the pond on the east side of the trail (Pond B). According to the DNR's September 3, 1993 survey, the overflow elevation of Pond A was 973.2, whereas for Pond B it was 973.9. In 1993, the overflows from Capaul's Pond filled Ponds A and B, causing overflows from the west pond (Pond A). From Pond A, water flowed westerly and southerly, filling a series of four depressions (Ponds D, E, F, and G). If Pond G were to overflow, water would flow to DNR-protected wetland #82-372W (Pond H) in Pine Plantation, in the City of Pine Springs. It F that in 1993 water from Capaul's Pond did not reach Pond H. If overflow from Pond Ii occurred, water would flow to the south basin of Long Lake (DNR-protected wetland #82- 371W). Therefore, Capaul's Pond was considered part of the Long Lake tributary area. A low home on Pond H (#82-372W) in the Pine Plantation development, would be flooded prior to overflow from the pond. As a result, the VBWD Managers voted in 1987 for MNDOT to direct the Capaul's Pond overflow to Pond I, since there are no low homes on that pond and it appeared to be the existing overflow route. In January, 1994, VBWD decided that any overflows from Capaul's Pond should again be directed to the east side of the DNR Gateway Trail south of T.H. 36 and to the pond in DeMontreville Highlands 3rd Addition (Pond I). VBWD based its decision on evidence of past Capaul's Pond overflows flowing to the east side of the trail and the inundation of many trees in the depressions on the west side of the trail (Ponds A, D, E, F and G). VBWD also decided that the Capaul's Pond overflow elevation should be maintained at Elevation 982.5 or higher. In response to VBWD's request and in cooperation with the City of Lake Elmo, the DNR lowered the overflow on the east side of the trail (Pond B) and unblocked the culvert under the access trail from the City of Lake Elmo's DeMontreville Park. DNR Trails and Waterways wishes to lower the overflow elevation to protect the DNR Gateway Trail from erosion. Considerable slumping of the trail into the wetlands occurred in the summer of 1993, as a result of the high water elevations. Based on the water levels in the different basins of Capaul's Pond, it appears that the DNR may have accidentally plugged the east end of the equalizer culvert when they repaired the slumped portions of the trail. Although overflows are infrequent, now that the runout elevation of Capaul's Pond is lower (from 982,9 to 982.5 or less), more frequent overflows from Capaul's Pond are likely, sending more water downstream to the pond in DeMontreville Highlands 3rd Addition (Pond 1). In addition, if development is proposed in the Capaul's Pond tributary watershed, more stormwater runoff will be generated which may cause Capaul's Pond to overflow more frequently. 23\82\045\SEC4.RPT\KMH 17 DRAFT: June 23, 1994