My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
Final Environmental Impact Statement Volume II Appendix K, Part 2
CWCB
>
Water Supply Protection
>
DayForward
>
5001-6000
>
Final Environmental Impact Statement Volume II Appendix K, Part 2
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
3/5/2013 1:20:44 PM
Creation date
2/27/2013 11:42:13 AM
Metadata
Fields
Template:
Water Supply Protection
Description
related to the Platte River Endangered Species Partnership (aka Platte River Recovery Implementation Program or PRRIP)
State
NE
Basin
North Platte
Date
7/1/1998
Author
Federal Energy Regulatory Commission (FERC) Office of Hydropower Licensing
Title
Final Environmental Impact Statement (EIS) - Volume II, Appendix K, Part 2 - Kingsley Dam (FERC Project No. 1417) and North Platte/Keystone Dam (FERC Project No. 1835) Projects, Nebraska, FERC/FEIS-0063
Water Supply Pro - Doc Type
EIS
Jump to thumbnail
< previous set
next set >
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
500
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
Show annotations
View images
View plain text
COMMENTS OF U.S. ENVIRONMENTAL PROTECTION AGENCY <br />Further, while considerable stream flow depletion occurred <br />prior to the construction of Lake McConaughy, the change in river <br />geomorphology was substantially accelerated after operation <br />began. (See Williams, "The Case of the Shrinking Channels - -the <br />North Platte and Platte Rivers in Nebraska ", Geological Survey <br />Circular 781, 1978, page 32.) As a result, the backwater areas <br />and wet meadows that provided temperate refugia to native aquatic <br />species have been significantly reduced. (See Currier et al., <br />Migratory Bird Habitat on the Platte and North Platte Rivers in <br />Nebraska. 1985.) <br />EPA conducted a review of the instream flows and ambient <br />temperature standards based on diminishing returns (Zander, <br />USEPA, July 1994, Enclosure B). Using the diminishing return <br />analysis, a daily instream flow of 900 cubic feet per second <br />(cfs) will reduce the frequency of exceedences of the state <br />temperature criterion of 32 °C to an acceptable level consistent <br />with state implementation of its water quality standards. The <br />"acceptable" level of temperature standard exceedence requires <br />that 900 cfs would be needed at all times, including during low <br />flow years. However, requiring release of this flow at any <br />7C reservoir storage level would significantly affect current uses. <br />in Allowing permittees to comply with CWA requirements normally <br />ON allows for exceedences during certain low flow conditions. NDEQ <br />00 uses a procedure to allow exceedences of permit limits during <br />extremely low flow conditions and EPA proposes that a similar <br />procedure be used to determine how frequent the 900 cfs is <br />required and when to exempt the facility from that requirement. <br />This method is the same process used by NDEQ for National <br />Pollutant Discharge Elimination System (NPDES) permit purposes <br />pursuant to section 402 of the CWA as described below. <br />NPDES permits are based on allowing water quality <br />exceedences when the receiving stream flow is below 7Q10 low flow <br />conditions. 7Q10 is defined as the average low flow for seven <br />consecutive days with a ten year recurrence interval for at least <br />a 10 year record. The 7Q10 flow for the Platte River at Grand <br />Island has a probability of exceedence of 90 percent. The storage <br />level for the last summer month, September, that has the same <br />probability of occurrence of 90 percent is 0.900 million acre - <br />feet (KAF) (using the baseline conditions for reservoir storage <br />from the OPSTUDY model). Therefore, 900 cfs as a daily limit for <br />summer flow at Grand Island must be maintained for storage <br />conditions above 0.900 MAF to meet the requirements of the <br />Nebraska state water quality standards in accordance with the <br />CWA. <br />EPA -10 I As lead agency for this relicensinq, FERC should include the <br />following as license conditions necessary to assure adequate <br />protection of the designated warmwater fishery use. (The column <br />on the right below should be substituted for the same column <br />presented on page 2 -31 of the RDEIS showing the daily instream <br />RESPONSES TO U.S. ENVIRONMENTAL PROTECTION AGENCY <br />EPA -10 We conducted a long -term simulation analysis using EPA's <br />recommended instream requirements. We found that fish survival <br />during the summer improves (from 95 percent exceedance for the <br />Nebraska Plan to 99 percent for the case with EPA flows), as does <br />the wet meadow indicator (from 69 percent to 79 percent <br />exceedance). Performance suffers, however, in winter bald eagle <br />flows (from 66 percent exceedance to 56 percent) and in drought <br />protection (from a minimum content of 414 KAF to 248 KAF). <br />On balance, we do not view this set of tradeoffs as beneficial. <br />Instead, the staff has revised its recommendations in light of the <br />basin -wide Cooperative Agreement. We endorse the various <br />measures comprising the FWS Reasonable and Prudent <br />Alternative, as described in the Agreement in Principle for License <br />Conditions for Project Nos. 1417 and 1835. <br />
The URL can be used to link to this page
Your browser does not support the video tag.