June 27, 2006
CFRTAC’s weekly summary of Milltown water quality monitoring data for the week of June 19-25 finds that the reservoir has dropped about eight feet and that turbidity has decreased substantially below the dam, and arsenic is down to background levels.
June 27, 2006
The Missoulian reports that the Clark Fork Coalition has received two planning grants from the Natural Resource Damage Program that look at additional sediment removal and land acquisition at the Milltown Reservoir.
The first grant examines the feasibility of removing an additional 350,000 cubic yards of sediment that would be left in place under the EPA’s cleanup plan. “We don’t believe that leaving a hazardous repository onsite is a good idea,” said Matt Clifford of the coalition. “Placing that rip-rap wall there doesn’t give the river a lot of room to move.”
The second grant, submitted with the backing of the Milltown Redevelopment Working Group, will appraise the value of Northwestern Energy lands in the reservoir area. The redevelopment group has called for public ownership of the lands at the Milltown site for trails and an interpretive center.
June 20, 2006
Water quality monitoring tied to the Milltown Reservoir cleanup is underway. Key to this effort is the now-final Remedial Action Monitoring Plan (RAMP) (PDF), which is designed to keep the river and groundwater from becoming polluted during all construction activities in the Milltown reservoir area.
CFRTAC’s technical advisor Chris Brick offered this summary of the first two weeks of monitoring:
The initial drawdown of the reservoir began June 1st, about two weeks after peak runoff, and the reservoir is currently about 6.7 feet lower, fluctuating slightly with flow in the river. The level will continue to drop as flow decreases until it is drawn down about 10 feet. So far it’s gone well, and water quality has been similar to other years of spring runoff. River water quality is being monitored closely, and the results are available daily at the following website: ftp://milltown.envirocon.com/ (Drag the “Surface Water Monitoring Data” folder to your desktop and open it on your computer, not on the ftp site.)
In the first week, turbidity (the cloudiness of the water measured in units known as NTUs) nudged up to the project standard, triggering daily sampling for arsenic, copper and total suspended solids. Arsenic and sediment were both high at Turah (above the dam), but remained below warning limits below the dam.
In the second week, heavy rain kicked up both flow and turbidity in the river. Turbidity was above the standard (12 NTU) most of the week, getting as high as 29 NTU. Daily sampling for arsenic, copper and total suspended solids continued, and these parameters remained below warning limits. The highest arsenic value in the river below the dam was 6 micrograms per liter.
By June 15th, flows in the river were declining along with turbidity, which fell below the 12 NTU trigger value. Both have continued to fall for the past couple days, and arsenic, copper and total suspended sediment have also decreased. Arsenic in the river is currently at 3-4 micrograms per liter.
June 17, 2006
From Peter Nielsen, Missoula County’s point person for all things Milltown, here’s a good summary of the first two weeks of the drawdown at the reservoir:
The Milltown Reservoir drawdown was initiated on June 1 in preparation for the removal of the Milltown Dam and cleanup of contaminated sediment at the Milltown Superfund site. The reservoir will be drawn down by about 8 to 10 feet below normal full poll elevation this summer. It will remain drawn down until next May, when spring runoff will partially refill the reservoir. Following spring runoff next year, the reservoir will drop again during the summer to 8 – 10 feet below normal full pool elevation.
Beginning in August of this year, work will be initiated on upgrades to the Interstate 90 bridges on the Blackfoot River arm of the Reservoir. The Highway 200 bridge and railroad bridge will also have work done to fortify them this fall and winter. This work must be completed prior to October 2007 when the reservoir will be drawn down an additional 7 feet to prepare for removal of the Milltown Dam (Stage 2 drawdown). The pedestrian bridge in Milltown will also be replaced with a new pedestrian bridge in 2007.
While the reservoir is drawn down this year and next year, Envirocon (Atlantic Richfield’s contractor) will build roads, berms, a rail spur and a bypass channel on the Clark Fork arm of the reservoir. In fall 2007, the Clark Fork River will be diverted into the bypass channel, prior to the Stage 2 drawdown. The Milltown Dam spillway is scheduled for removal in early 2008. Following its removal, the reservoir will drop the final 12 feet and the river will be restored to its final channel elevation.
The reservoir water elevation was drawn down by 6.4 feet this afternoon. The water level in the reservoir is currently controlled by river flows, and will continue to drop gradually as the river drops through the remainder of June and into July. It only dropped about 0.16 feet in the last 24 hours, and the rate of drawdown may be as little as 0.1 to 0.4 feet per day in the coming week, depending on river flows.
So far the drawdown has gone well, and downstream water quality has been similar to that which routinely occurs during spring runoff. River water quality is being monitored closely, and the results are available daily at the following website:
Turbidity levels in the river increased above 12 turbidity units last week, requiring daily sampling of the river for suspended solids, metals and arsenic. Due to heavy rainfall in the Clark Fork headwaters last weekend, river flows increased along with turbidity, arsenic and metals upstream and downstream of the Milltown Dam. Contaminant levels upstream of the dam on the Clark Fork were higher than those detected downstream. For example, arsenic levels were as high as 13 parts per billion upstream of the dam this week, while arsenic concentrations were as high as 6 parts per billion downstream.
Water quality in the river has cleared up significantly Thursday and Friday. Turbidity levels in the river were down to 7.5 units this morning. Suspended solids, copper and arsenic concentrations downstream of the Milltown Dam are at fairly typical levels for this time of year during spring runoff, and well below the warning limits established for the project. Dissolved arsenic was at 4 ppb yesterday (the warning limit is 8 ppb) and the copper concentration was 4 ppb (with its warning limit at 20 ppb.) Even though the dissolved arsenic below the dam was somewhat elevated, the data for the CFR at Turah showed a value of 8 ppb for dissolved arsenic.
Domestic well and monitoring well sampling was conducted in late May and the first week of June, and results will be posted on the ftp site in the near future. All wells in the monitoring program will be monitored again at the end of June. The monitoring well network includes private and public supply wells, and monitoring wells surrounding the reservoir and extending downstream into Missoula. Additional wells may be added to the monitoring well network in the unlikely event that arsenic levels in the river or in wells increase significantly.
Contingency plans have been finalized for domestic well contamination, exceedance of standards in the river, and for cleanup of irrigation intakes. These contingency plans and the remedial action monitoring plan can be downloaded from another web site:
Other design documents are also available at this website
June 15, 2006
The Milltown Reservoir cleanup is a major construction project and this report describes conceptually everything necessary to carry out the work. It includes the construction of flood control berms, haul roads, rail spurs, and offices. It also explains how the old landfill will be removed, where borrow areas for soil and fill will be and how stormwater will be managed. Check back soon for CFRTAC’s summary-review.
Comments from Milltown Design Review Team (DRT) members (PDF) on this PDR are due to EPA on June 23rd. The interested public can contact DRT members directly or CFRTAC with comments and questions.
June 15, 2006
June 7, 2006
BP-ARCO has released a fugitive dust management plan (PDF 1.6 MB) for its repository near Opportunity. Dust from its 3500-acre repository and other sources is both a historic and current problem. Local residents have been increasingly vocal about the possible health effects of airborne dust, which at times clouds the area around Opportunity, Warm Springs and even as far as the town of Deer Lodge.
Check back soon for CFRTAC’s technical review of the plan. Also, see the June CFRTAC newsletter for more on BP-ARCO’s dust problem in Opportunity.