Flood Survey Report
Independent surface water flooding; locations, evaluations and recommendations related to severe storm on August 1, 2007
Participants:
Roger Phillips, Dammeron Valley resident
Brooks Pace, DV resident and developer
Mac Thomson, DV resident
On August 14, 2007, the participants began the review aided by an aerial photo showing highway 18 and Dammeron Valley. Noted on the photo were highway culvert locations and sizes of culverts noted in 2005, as well as approximate water flow locations in Dammeron Valley following that year's above normal storm.
Using the photo and subdivision overlay as references, the following are our approximation of problem areas as well as recommendations to either reduce or negate future storm water damage to residences and/or property.
Our review started at mile marker 16 on highway 18 and proceeded north on highway 18. Culvert #1 is located approximately 200 yards north of mile marker 16. It is + or - 5'6' in diameter. Debris is piled 18-24 inches above the culvert neck on the highway road bed. It could not handle the water volume from the drainage channel and the surplus water headed north parallel to the highway and began to cross the highway moving west and did that continuously for over two miles according to debris flow patterns as well as Thomsons observations during the August 1 storm.
What waters did pass through the next two culverts as well as over road flow also took a westward flow pattern into the Dammeron Valley development beginning at the southeast corner of Dammeron Valley causing some surface damage to two lots.
All water crossing highway 18 (from 1' to 12' +) westbound entered Dammeron Valley in sheets or flow and proceeded northwesterly across properties. The most severe damages were related to:
Homestead Road west and intersections at Meadow Drive
Old Farms Drive and Dammeron Valley Dr. West
At all these intersections there is no sign of adequate or existing drainage nor culverts. Several homes were damaged on Old Farms Rd.
Water then proceeded northerly along Old Farms Rd. to Dammeron Valley Dr. West and was further increased in volume by a westerly highway overflow to approximately mile marker 18. These waters either flowed through the east side of the Old Farms subdivision or west on Dammeron Valley Dr. West where they crossed the road and continued west through a pasture then followed a fence line and were joined by the northerly flow which had crossed Orchard. These combined waters damaged property on Orchard, crossed Wild Herb Rd. prior to Coyote Way and damaged 2 more homes. The flow continued west on Coyote Way to the large lake that normally accumulates at Coyote Way and Homestead due to a lack of a culvert or ford. The water from that point tends to follow Homestead west, building from overland flow from the north and east until it leaves Homestead after running over and through several lots and crossing in to and across Sand Cove Circle and 3 lots there including the west end of the Pinion Hills leach field ending up at Upper Sand Cove reservoir area.
The east side of Dammeron Valley from highway 18 was primarily affected by overland water flow beyond that which the Bonnie Springs normal channel could carry, across highway 18 westward damaging properties at the end of Carter Pond Rd.
Recommendations:
UDOT replace culverts #2 and #3 with a second high capacity culvert similar to culvert #1 and direct that water southwest to join that flow of culvert #1 for natural drainage westward.
Develop a large barrow ditch from culvert #3 parallel to highway 18 on the east side, north to the north end of Dammeron Valley west (natural Bonnie Springs drainage to Sand Cove) and block off existing east to west culverts ( 3 through 13); use either fords or high volume squash culverts for east entrances to Dammeron Valley and side roads on east side of highway 18. Use high capacity box culvert to carry entire flow east to west under highway 18 to natural channels ending up at Upper Sand Cove area.
Washington Co. Road Department. Correct/upgrade all roadside barrow drainages within subdivision and install proper culverts and right-of-way armoring. Require all landowners that need culverts to install code required sizes.
Install adequate culverts at all intersections to direct water to desired locations.
Reinstall the ford at the end of Carter Pond Rd. or at least culverts of a capacity to carry newly directed flow or as a minimum, the capacity of water now directed by the 4 each 36รข€ culverts that cross highway 18. (identified as 14-17) at the natural Bonnie Springs drainage location.
Direct water parallel to Homestead Drive westerly to the Dammeron Valley SSD lot/Pinion Hills leach field into a ditch running northerly east of the leach field to protect the leach field and Sand Cove Circle homes.
Washington Co. Road Department could consider capture of the westerly water flow at Wild Herb Rd. and direct it north to State land after crossing Coyote Way in a ditch to reduce total flow west on Coyote Way.
Washington County should look at existing building codes and modify if necessary the height of new home pads/basement walls, above ground surfaces, if street water flow is anticipated in newly developed areas.
Dammeron Valley Developers:
Anticipate high surface water flows based on natural topography when creating new CC&Rs for future subdivisions in Dammeron Valley and realizing that with each home built, there will be more water run-off even on gently sloping lands. Surface vegetation or other features for landscaping should be encouraged to slow water flow and encourage percolation versus run-off.
All Dammeron Valley Residents:
Landscape as necessary to not only protect your own homes but also so as not to create greater hazards to your neighbors downstream. Try to slow surface water to aid percolation - not funnel it so that it channels, erodes and washes debris downstream
