My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
EIS Arapahoe & Roosevelt National Forest, Pawnee National Grassland
CWCB
>
Water Supply Protection
>
DayForward
>
1001-2000
>
EIS Arapahoe & Roosevelt National Forest, Pawnee National Grassland
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
1/26/2010 4:38:28 PM
Creation date
6/15/2009 11:45:54 AM
Metadata
Fields
Template:
Water Supply Protection
File Number
8461.250
Description
Water Issues
State
CO
Basin
South Platte
Water Division
1
Author
USDA, Forest Service, Rocky Mountain Region
Title
EIS Arapahoe & Roosevelt National Forest, Pawnee National Grassland
Water Supply Pro - Doc Type
EIS
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
45
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
Chapter 3- Affected Environment and Consequences <br />Riparian and wetlands assessment <br />? The Forest is using an approach called Proper Functioning Condition (PFC) to assess the status <br />of rip rian and wetland areas (Bureau of Land Management 1995). This field-level process <br />evalua es the interaction of three components: vegetation, landform/soils, and hydrology. The <br />proce: s of assessing whether a riparian/wetland is functioning properly requires an interdiscipli- <br />nary team. For riparian/wetland areas to function properly, adequate vegetation, landform, or <br />large ? oody debris must be present to dissipate stream energy associated with high watertlows. <br />Appro? riate dissipation of stream energy reduces erosion, improves water quality, aids flood- <br />plain ? evelopment, stabilizes streambanks, and develops the channel characteristics which <br />provid habitat for fish production, waterfowl breeding, and other uses. The PFC process is <br />used c uring project-level ana(ysis to access the condition of riparian/wetiand areas <br />1--? Environmental Consequences I <br />Direck and tndirect Effects <br />Surface water, groundwater, riparian, and wetlands areas are all ciosely reiated. They will be <br />dealt i ith together since effects to all of them are similar. When they are impacted differently, it <br />wil( be specifically noted and described. <br />The p tential for effects to watersheds, riparian and wetlands is directly-tied to activities that <br />impac and disrupt these areas. Impacts could be from activities that physically impact the area <br />by util zing vegetation to disrupting surface or subsurface water flow to these area. <br />Effec1 from Timber Harvesting - Timber harvest at the fuA budget implementation level <br />ranges by altemative from 663 acres of disturbance to 3,644 acres of disturbance per year, <br />includ ng aspen and road construction. Variations in volume, acres of harvest by prescription <br />type, of roads constructed and reconstructed, acres of soil and water improvements and <br />numb' ri'es <br />of watersheds entered vary by alternative, shown in Table 3-11. <br />l <br />A res It of timber hanresting is increases in water yield due to the removal of trees which <br />transr ire water, which increases the amount of surface water. Increases occur as increased <br />snowr elt runoff flows, causing both the peak flow to increase in intensiiy and duration above <br />baseli e conditions. These increased flows can cause stream channel scour, which can lead to <br />exces in-channel sedimentation. <br />In adc ition to an increase in avaifable water for surface fiows, ground-based togging methods <br />used on the Forest can increase surface nmoff further. Skid trails, roads and iandings can <br />comp ct soils, reducing infiltration and increasing connected disturbed areas within those water- <br />shed: harvested. Connected disturbed areas extend the effective stream channel system within <br />a wa ershed, thus increasing surface runoff and stream sedimentation. These additional <br />increz ses in streamflows can increase stream channel scour and decrease watershed condition <br />poten ial further. <br />Incre? ses in water and sediment yieids beyond ievels that a stream system can tolerate cause a <br />strear to lose equilibrium. Pools fill, and the stream channel characteristics change and resutt in <br />a los: of aquatic habitat. Streambanks can become unstable, accelerating the problems further. <br />Wate? yield increases due to timber harvest. Altemative E would produce the largest amount of <br />water and Altemative F the least. Altematives A and G would produce the next highest amount <br />of wa er followed by Alternatives D, C, B and F. Higher water yield increases the risk of reducing <br />streai and watershed potentiaf. Risk of decreased stream channel stabitity and watershed <br />poten ial due to water yield increase is highest with implementation of Altemative E fo(lowed in <br />order of risk by Alternatives A, G, D, C, B and F. Water yiefd increase is not directly correlated to <br />3-46 1 Routt National Forest - ElS (Water/R/parJan/WeUands)
The URL can be used to link to this page
Your browser does not support the video tag.