Environmental Engineering Reference
In-Depth Information
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4
6810
12
14
0
20
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100
-20
-20
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-40
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-60
-80
-80
-100
-100
-120
-140
-120
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-160
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-200
Dissolved oxygen (mg L -1 )
Te mperature (ºF)
4500
4000
3500
3000
2500
2000
1500
1000
500
0:00
4:48
9:36
14:24
19:12
Time (h)
0:00
4:48
9:36
14:24
FIGURE 18.9 Temperature and oxygen vertical proiles near the dam and turbine releases for Bull Shoals
Lake for July 11-12, 2012. (Data from USACOE Little Rock District Water Management online project data
reports, Available at http://www.swl-wc.usace.army.mil/.)
isheries would not exist. So, in times of water shortages, or drought conditions, the lack of water to
support the isheries became a major problem. The USACE (2008) indicated that worst-case con-
ditions were 3-day weekends during the summer months with minimum hydropower generation,
when the pools in the river became isolated by shoals and prevented trout from seeking refuge. But,
with the absence of a designated project purpose, the reservoir could/would not be operated to sup-
port and protect the downstream ishery.
Decades of concern and negotiation led to authorized studies (in Section 375 of the 1999
Water Resources Development Act), including environmental impact studies under the National
Environmental Policy Act (NEPA), and then authorization (in the 2006 Energy and Water Development
Appropriations Act; Public Law 109-103; USACE 2008) that led to the establishment of reallocations
of water storage for minimum lows. For example, under the authorized plan for the Bull Shoals proj-
ect, 5 ft. of storage for minimum lows was to be reallocated from the lood control pool with provi-
sions to provide a portion of the reallocated storage for the hydropower's use to maintain the yield
of the current hydropower storage. In addition, for Bull Shoals, additional releases to maintain the
minimum low were to be implemented by generating power with one of the main units at a low rate.
Since the change in storage impacted the economics of power generation, the 2006 act required
a determination of compensation necessary for losses of income from hydropower. SPAW (2009)
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