Engineers Advise Homeowners about Snowmelt, Runoff …Crested Butte News
Snow pack in the Gunnison Basin is 140 percent to 160 percent of average. Recent climate patterns indicate that spring snowmelt will have a rapid runoff in local creeks, rivers, and even ephemeral drainages.
Engineers and geologists at the Crested Butte and Gunnison offices of Buckhorn Geotech, Inc. are concerned about adverse impacts of the higher the usual runoff. Steps should be initiated early to limit potential damage. Potential damage may come from overtopping of small storage ponds and reservoirs, erosion of stream banks and ditches, destruction of diversion structures, flooding along creek banks, and damage to roads, especially at bridge and culvert crossings.
Keep in mind that if a home or other structure sits in a low area, water will drain towards it unless berms or other drainage features deflect the runoff away from the home.
An unseen result off the huge runoff is higher than normal groundwater resulting in crawlspaces, seepage into basements and the triggering of landslides.
Some of the precautions that can be taken early are to clean and clear culverts, spillways, outlet structures and borrow ditches. Removing snow piles and ice dams soon can prevent inadvertent flooding of adjacent areas. If possible, snow should be removed from the immediate vicinity of a house and where meltwater pools, trenches should be dug to allow the water to drain away from the house. If water saturates the soils around a house, water can enter the basement or crawlspace, which will require dewatering. Saturation of soils beneath foundations presents the possibility of foundation movement. When wetted, weak soils can compress, causing a foundations to settle, while clayey soils can expand causing a foundation to heave.
In some cases, it may be necessary to use straw bales or other such materials along drainages to slow down the velocity of or temporarily store water during peak flow periods. Spring will soon be upon us and water will be flowing from the deep bank of snow. Now is the time to prepare for the high water. If you have questions, or we can be of service, Buckhorn Geotech can be reached at (970) 349-9100 in Crested Butte or (970) 641-3793 in Gunnison.
The following websites contain information regarding snow pack, water data, and/or stream flow volumes in Colorado:
http://www.wrcc.dri.edu/snotelanom/snotelbasin
http://www.dwr.state.co.us/SurfaceWater/Default.aspx
http://www.wcc.nrcs.usda.gov/snotel/Colorado/colorado.html
http://waterdata.usgs.gov/co/nwis