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Forest Watershed Management
Course Objective:
Understand the purposes and procedures of watershed management, the impact of forest management activities on water yield and quality, the role of best management practices (BMP’s), and the role of foresters in BMP implementation and watershed management.
Grading
Grades are based on:
• Three quizzes - 20%
• Final examination - 30%
• Project - 40%
• Class participation - 10%
Research Paper• Due Date: November 1, 2006• Length: 1,200 words• Topic: Describe a typical forested watershed for your
forest cover type. The description should include – (1) geomorphology and soils, – (2) terrain,– (3) annual and seasonal precipitation patterns (use graphs), – (4) frequency and severity of storm events (use graphs), – (5) steam flow patters (include a hydrograph for a storm event if
available), – (6) stream sedimentation rates with continuous forest cover and
with haul roads and skid trails (do literature search), – (7) the composition of the forest layers associated with the cover
type, including the duff layer, if any.
What Is A Watershed? Also referred to as a “catchment”
• Topographically delineated area drained by a stream system– No specific scale implied
• Total land area above a designated point on a stream or river that drains past that point
• For planning and management purposes it’s a– Physical-biologic unit
– Socioeconomic-political unit
Watershed Name: TippecanoeUSGS Cataloging Unit: 05120106
http://cfpub.epa.gov/surf/locate/index.cfm
Why Study Forest Watershed Management?
• Historically focus was forest hydrology– Hydrological effects of
vegetation and land management practices on water quantity and quality, erosion, and sedimentation at specific sites
• Hydrology – Science of water
concerned with the origin, circulation, distribution, and properties of the waters of the earth.
Sources of Soil Erosion –“It’s All Relative Folks”
• Construction sites• Cropland• Forest roads• Forest land
12T/A/Yr
Soil Erosion on Forest Land Piedmont Region of Southeastern U.S.
= 0.4 tons/acre/year
= 0.04 tons/acre/year
(con
v ers
ion
fac t
o r: k
g /h a
x 0
.892
183
= lb
/ac r
e )
Source: John D. Hewlett. 1982. Principles of Forest Hydrology, Univ. Ga. Press, p. 150
Forest Activities & Soil Erosion(in order of contribution to erosion)
• Roads and skid trails• Channel encroachment• Site preparation• Harvesting activities• Fire prevention and suppression• Recreation activities• Flatwoods drainage• Wildlife management activities
Source: John D. Hewlett. 1982. Principles of Forest Hydrology, Univ. Ga. Press, p. 149
Hydrologic Affects of Silvicultural Practices
• Clearcut– Expose mineral soil– Increase soil
temperatures– Reduce
evapotransporation– Increase exposure to
wind and associated evaporation
– Increase erosion and stream sedimentation
Hydrologic Affects of Road Systems
• Creates impermeable surface– Increases surface flow
– Channelizes surface water flow
– May channelize shallow subsurface flow
Forest Watershed Management
• Clean Water Act – Sec. 1329 focuses attention
of forest land through nonpoint source pollution requirements
• Citizen interest– Poor practices would cause
shutdowns of forest operations
• Best management practices (BMP) adopted in most states
An Issue in All States
• Areas of abundant rainfall– Impacts of
storm events
• Droughty areas– Capture and
allocation of available water
Best Management Practices• Focus of forestry and forest products community• BMP’s are either regulations or guidelines for silvicultural
activities– Planting– Harvesting– Roads
• Usually emphasize water quality
Focus of Course: Knowledge to Implement Forest BMP Practices
• Understand action of water in forest environments
• Knowledge of applicable BMP’s
• Skill to apply BMP’s to a specific project on a specific site
Knowledge of Precipitation Amounts and Patterns
• Plan drainage structures– Size temporary
culverts to handle storm events during period of operations
– Size permanent drainage structure to handle 100 year storms
Knowledge of Precipitation Amounts and Patterns
• Time operations– Expose soil during dry periods if possible– Establish vegetative cover as soon as possible– Use native vegetation whenever possible
Become familiar with precipitation patterns
• Sources of data– NOAA
– NWS
– State climatologist• Usually at Land
Grant University
• Vast amount of data available on line
National Weather ServiceNational Weather Service
Indiana Climate Pagehttp://shadow.agry.purdue.edu/index.html
Variation in Precipitation
• Random• Seasonal• Proximity to water
body (lake affect)• Prevailing winds
with moisture• Topographic
Seasonal Variation
Indiana Total Precipitation
0
1
2
3
4
5
Jan.
Mar.
May
July
Sep.
Nov.
Month
Inch
es
NC
SC
State
Proximity to Water Body
Prevailing Winds
Topographic Affect
• Rising air cools• Dew point reached• Water vapor
condenses to form clouds
• Precipitation may occur
• Cloud patterns induced by passage of air current over mountains
• Precipitation concentrated on windward side of mountain, and mountain top
• Tends to be rain shadow on leeward side
• Fidalgo Island in rain shadow of the Olympic Mountains.
• Rainforests with up to 200 inches of precipitation on the west side.
• Rain shadow area northeast of the Peninsula with only one-half (20 inches) of the normal rainfall for the rest of the region.
Avg. Monthly Rainfall 1931-1998
02468101214161820
Month
Inch
es
Clearwater 118.5”
Coupeville 21.14”
Puget Sound Area, Washington
Storm Events, 1st Qtr.
Daily Precipitation, Bedford, IN, 1998
00.20.40.60.81
1/1/99
1/8/99
1/15/99
1/22/99
1/29/99
2/5/99
2/12/99
2/19/99
2/26/99
3/5/99
3/12/99
3/19/99
3/26/99
Inch
es
Storm Events, 2nd Qtr.
Daily Precipitation, 1998, Bedford, IN
012345
4/1/99
4/8/99
4/15/99
4/22/99
4/29/99
5/6/99
5/13/99
5/20/99
5/27/99
6/3/99
6/10/99
6/17/99
6/24/99
Inch
es
Storm Events, 3rd Qtr.
Daily Precipitation, 1998, Bedford, IN
00.20.40.60.81
1.2
7/1/99
7/8/99
7/15/99
7/22/99
7/29/99
8/5/99
8/12/99
8/19/99
8/26/99
9/2/99
9/9/99
9/16/99
9/23/99
9/30/99
Inch
es
Storm Events, 4th Qtr.
Daily Precipitation, 1998, Bedford, IN
00.51
1.52
2.5
10/1/99
10/8/99
10/15/99
10/22/99
10/29/99
11/5/99
11/12/99
11/19/99
11/26/99
12/3/99
12/10/99
12/17/99
12/24/99
12/31/99
Inch
es
Monroe County Airport, April 15-16, 1998
15th 0953 .03
1053 .26
1158 .00
1253 .01
1353 .0
1453 .04
1553 .0
1953 .14
2053 .12
2153 .10
2253 .36
2353 .17
16th 0053 .32
0153 .22
0253 .25
0353 .08
Hourly Precipitation
0
0.1
0.2
0.3
0.4
Series1
Some Basic Hydrologic Concepts
Weir are used to measure volume of water flowing past a point.
What Happens to Precipitation?
• Hydrologic cycleP = RO + ET + S,
Where,• P ≡ precipitation
• RO ≡ runoff
• ET ≡ evapotranspiration
• S ≡ storage
Evapotranspiration
• Loss of water from a given area during a specified time by evaporation from the soil surface and by transpiration from the plants.
• Supports plant life• Reduces water yield
Runoff Provides Major Benefits RO = P – ET
Moose Creek, Clearfield County, PA (WLH)
Where does runoff go to?
• RO = CI + SRO + SSF + BF, – where,
• CI ≡ channel interception• SRO ≡ surface run off • SSF ≡ subsurface flow• BF ≡ base flow
Where does runoff go to?
– CI ≡ channel interception• Precipitation falling directly into
channel
Susquehanna River, Clearfield, PA, (WLH)
Where does runoff go to?– SRO ≡ surface runoff or overland flow
• Precipitation not infiltrating soil
Sheet erosion of cropland resulting from surface runoff
Source: http://www.agric.gov.ab.ca/agdex/500/72000003.html
Where does runoff go to?
– SSF ≡ subsurface flow, or interflow• Infiltrating precipitation intercepted by hardpan or
bedrock before entering groundwater pool
Where does runoff go to?– BF ≡ base flow or ground water flow
• Precipitation entering water table
What We’ll Look At
• Erosion– Impacts of
• Roads• Harvests
• Water flows– Storm events– Storage
• Water yield– Amount– Timing Montgemory Reservoir, Clearfield, PA, WLH
