Warm Springs Ponds 



The headwaters area of the Clark Fork has a multitude of 

 heavy metals sources. A large part of the metals load in 

 Silver Bow Creek is attenuated by the Warm Springs treatment 

 ponds. However, the ponds are filling with sediment, and as 

 their capacity diminishes, so will the level of treatment 

 they provide. The ponds were designed to contain flows of 

 about 700 cfs, but much smaller flows have been diverted 

 around the ponds into the Mill-Willow Bypass because of dike 

 failure or collection of debris on the gates. When the ponds 

 are bypassed, untreated Silver Bow Creek water enters the 

 Clark Fork, and metals concentrations rise, often above EPA 

 acute aquatic-life criteria. In addition, intense summer 

 thunderstorms can cause fish kills by mobilizing metals that 

 have accumulated in the bypass. If the pond dikes failed 

 because of earthquake or flood damage, millions of cubic 

 yards of toxic sludge and sediments could be released to the 

 river. 



As a whole, the Warm Springs Ponds system has been a 

 useful sediment trap for Silver Bow Creek and has greatly 

 improved water quality in the Clark Fork. However, the fact 

 that water is frequently diverted around the ponds demon- 

 strates the need to improve the system to control and reduce 

 the movement of dissolved and suspended toxic elements from 

 Silver Bow Creek into the Clark Fork. Stabilizing the Warm 

 Springs Ponds against floods and earthquakes and improving 

 the long-term efficiency of the system are also critical. 

 These goals could be accomplished in a number of ways: 



1. Renovate the existing Warm Springs Ponds system and 

 stabilize the pond dikes to prevent damage and loss 

 of contents during floods or earthquakes. 



2. Renovate the Mill-Willow Bypass. 



3. Improve the treatment efficiency of the ponds and/or 

 expand the treatment pond capacity. 



These alternatives would be expensive, but they would 

 probably be cost-effective in the long term. The ponds 

 represent a pivotal point in the Clark Fork Basin, and 

 improvements in the system are critical to the amelioration 

 of the heavy metals problem in the Clark Fork. 



The Warm Springs Ponds system is currently a top 

 priority operable unit within the Silver Bow Creek Superfund 

 site. A feasibility study report that will define alterna- 

 tives for the system is due out in early 1989. At that time, 



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