Animas River watershed: Lightner Creek sediment is fouling the river
October 24, 2010
Here’s a call to action from Buck Skillen writing in The Durango Herald. From the article:
Why is this sort of turbidity – what I choose to call the Lightner Creek problem – happening at this time of year? One possible cause of the current problem is a substantial rain event back on Sept. 13 that dumped upwards of an inch of water on Durango and the Perin’s Peak area.
The Perin’s Peak geology is predominately Mancos shale, which is easily eroded. This area drains into Lightner Creek predominantly through Perin’s Canyon, where there is a 4-foot-diameter culvert delivering the canyon’s flow into Lightner Creek.
The storm on Sept. 13 delivered a huge volume of sediment to the creek, damaging the culvert and depositing a substantial amount of sediment in the creek bed. Since that time, and especially after the more recent storms, we are seeing the slightest amount of current in Lightner Creek pick up the fine sediment and transport it to the Animas River.
Why should we care? The Animas River is the city of Durango’s crown jewel. It’s a playground for all of us, visitors and locals, both in the water and walking along the River Trail, and a source of revenue from recreation. A good portion of our drinking water comes from the intake structure downstream of Lightner Creek and just above Smelter Rapids, although I am told this is not a big concern for the water treatment plant.
More Animas River watershed coverage here.
Durango: Study of sediment sources in Lightner Creek underway
October 31, 2009
From The Durango Herald (Dale Rodebaugh):
A coalition of public agencies has acquired funding for a three-phase hydrological study to answer questions that have stumped observers for years: Where does the sediment that Lightner Creek periodically dumps into the Animas River come from, and why? Field work on the study, begun this week, could be done by the end of the year and lead to answers to an environmental problem seen as a potential source of harm to renowned fishing waters. “Sediment comes and goes, but no one knows whether it’s natural or human-induced,” Meghan Maloney, river campaign director at the San Juan Citizens Alliance, said recently. “The reason for concern is that Lightner Creek runs into the Animas at the head of a trout fishery that the Colorado Division of Wildlife gives its highest rating – gold medal.”[...]
Three organizations put up funding for a study – Trout Unlimited $1,000, the Colorado Water Conservation Board $5,000 and the Southwestern Water Conservation District $2,600 – to hire Mark Oliver of Basin Hydrology. Oliver started his field work this week. “I started at the mouth where Lightner Creek runs into the Animas and I’m working my way upstream,” Oliver said. “I’m looking at the channel and flood plain for sediment sources that could come from bank erosion or land-use modification. “The Tech Center watershed and Perins Canyon seem likely sources of silt,” Oliver said. “But my study will confirm whether the deposition is coming from there.” At certain points, Oliver will do sieve analysis – measuring the size of sediment particles. Along with a cross-section analysis of the channel – width, depth and slope – he can determine the movement of sediment. “I’ll focus on sediment sources and the mechanics of how sediment gets to the mouth,” Oliver said. “Then I’ll try to determine if the sediment is natural or caused by people – for example, the landfill above the Tech Center.”
