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Home My WebLink About20030147 Ver 2_WRC Comments_20071022~~ North Carolina Wildlife Resources Commission ~~~ Mr. John Dorney Division of Water Quality 401/Wetlands Unit 1650 Mail Service Center Q~c~~oe~~ ~~T 2 2 207 DENR -WATER QUALITY Raleigh, NC 27699-1650 YMros~tia~->~sRBFtANC.~ Subject: Application for Section 401 Water Quality Certification Progress Energy's Yadkin-Pee Dee River Hydroelectric Froject (FERC P-2206) Montgomery, Stanly, Anson and Richmond Counties DWQ Project Number 2003-0417 version 3 Dear Mr. Dorney: The North Carolina Wildlife Resources Commission (NCWRC) has reviewed the application for a 401 water quality certification submitted by Progress Energy in conjunction with the license application submitted to the Federal Energy Regulatory Commission (FERC) for Progress Energy's Yadkin-Pee Dee River Hydroelectric Project. The NCWRC has previously commented on Progress Energy's 401 Certification application. These previous comments included conditions which we think should be included in the 401 Certification. We are submitting these supplemental comments in response to the public hearing held in Richmond County on 18 September 2007. The NCWRC supports the flow regime proposed by Progress Energy through the Comprehensive Settlement Agreement (CSA) for the Pee Dee River below Lake Tillery. This proposal includes a continuous yeaz-round minimum flow of 330 cfs, and a release of 725 cfs for eight continuous weeks starting between 15 March and 22 Mazch. A summary of the analysis of benefits to aquatic life of this flow regime has been submitted for consideration by the NC Division of Water Resources (letter from Mr. Jim Mead to Mr. John Dorney dated 19 October 2007) and will not be restated here. However, the NCWRC also used the concept of wetted perimeter and visual observations in determining if the proposed flow regime provided a suitable level of protection for aquatic life. Wetted perimeter is the amount of stream channel covered by water at various levels of discharge. In wetted perimeter analysis, the length of the stream channel covered by water is plotted against various discharges. The flow at or neaz the Mailing Address: Division of Inland Fisheries • 1721 Mail Service Center • Raleigh, NC 27699-1721 Telephone: (919) 707-0224 • Faa: (919) 707-0228 PAGE 2 19 OCTOBER 2007 breakpoint in the graph is then selected as the minimum flow. As part of the Instream Flow Study, Progress Energy provided wetted perimeter -discharge relationships for several locations along the Pee Dee River. Three of these locations were in the reach between the Tillery Dam and the confluence with the Rocky River. This reach is considered to be most affected by operations of Tillery Dam due to the close proximity. The wetted perimeter -discharge relationships for the three near-dam transects are provided in figure 1. Note that at transects 7 and 8, the proposed minimum flow of 330 cfs is greater than the minimum flows indicated by the breakpoint. At transect 3, the proposed minimum flow is slightly less than the minimum flow indicated by the break point. These wetted perimeter graphs show that most of the channel is inundated at the proposed minimum flow of 330 cfs. This should be beneficial for benthic-dwelling organisms such as mussels, aquatic insects, crayfish, and darters. It should also be beneficial to many other fish species by providing for increased food production in the form of benthic macroinvertebrates. Also, not only is the majority of the stream bed inundated by the 330 cfs, most of the large substrates are covered as well (see figures 2-5). One of the major criticisms of using the wetted perimeter technique is that it is only sufficient for providing for minimum flows and does not allow for infra-annual variability. However, the flow regime proposed by CSA dictates that the minimum flow increase to 725 cfs during eight weeks in the spring when higher flows are needed by spawning fish. As such, the proposed flow regime accounts for both the low flow seasons and the higher flow needed during the spring months. For these reasons as well as those stated by the Division of Water Resources, the NCWRC supports the flows proposed in the Comprehensive Settlement Agreement and feels that they will be protective of aquatic life in the Pee Dee River below Tillery Dam. Feel free to contact me at todd.ewing~a,ncwildlife.org or (828) 874-0494 if you have any questions or need clarification on any of the above comments. Sincerely, ~~~ , Todd D. Ewing Eastern Hydropower Coordinator Division of Inland Fisheries NC Wildlife Resources Commission attachements PAGE 3 19 OCTOBER 2007 800 700 .-. 600 a~ 500 a~ E ~~ 400 d 300 a~ ~ 200 100 0 0 200 400 600 800 1000 1200 Flow (cfs) • Transect 8 • Transect 7 • Transect 3 Figure 1. Wetted perimeter -discharge relationships for the three near-dam transects in the Pee Dee River below Tillery Dam. Red points indicate the proposed minimum flows. PAGE 4 19 OCTOBER 2007 s 3 :~~ 4~}F,~ ~ ~, # ~5 ~~ ~E . «:.,,r ~^.~ ~ ~:'~`_' ;. ,'a E_:,..,~ :fit. . ~- - _ _ - - -_- - -__ =.,-„ F ,. ~... - _ •-.~. ,..:. »,-, - - _ .~'"= - _ °-"~--tea- , ~~ -_ -~„ ~-~.~-- .. ~, :.~ ~ ~` - ~~•. h- - - - - -_ .. __ ~~ 1 ~e*s~i ..~ - ~: '- '~. r - ~. _~ " ~_ ,~ s s ~ += ~ _ ~ .mow:. ~~'~ ~~r~ .. __ s ~~~ _ -- - ~. Figure 2. Looking upstream at Tillery Dam from transect 8 under the current minimum flow (~ 50 cfs). Note the exposed substrate. PAGE 5 19 OCTOBER 2007 Figure 3. Looking upstream at Tillery Dam from transect 8 under the proposed flow (~ 330 cfs). Note that most of the substrate is covered under this flow. PAGE 6 19 OCTOBER 2007 =s .°_' ,~~~~ __ ~1~.^ Figure 4. Looking downstream from transect 7 at the current minimum flow (~ 50 cfs). Note the exposed substrates. PAGE 7 19 OCTOBER 2007 ~. `-~ :,, "_~-- _ ~=tom Figure 4. Looking downstream from transect 7 at the proposed minimum flow (~ 330 cfs).