WSP09868

• File Number: 8200.700
• Description: Colorado River Basin - General Publications
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 2/1/1984
• Author: Colo Div Water Resou
• Title: A Literature Review of the Effect of Timber Cutting on Water Yield - State Engineer-Colorado Division of Water Resources
• Water Supply Pro - Doc Type: Report/Study

~ '
j

,
~

.
.
!
)
.,
j

j
j.

"

.

.

000662

(1)

Wa tershed ~lanageJnent in the Central and Southern Rocky Mounta ins:
mar~ of status of our knowledge by vegetation types, by Charles
USV , 1-S, Rl>1-14Z, 1915.

The report summarizes ;J series of comprehensive reports during 40 or 50
years (prior to 1975) on watershed management on five major vegetation types:
0) the coniferous forest subalpine zone, (2) the Front Range ponderosa pine
zone, (3) the Black Hi Us Ponderosa Pine zone, (4) the alpine zone, and (5)
the big sagebrush zone. The conclusions of the author are:

A sum-
F. Leaf,

1. Patchcutting subalpine forests results in significant redistribution
of winter snol>pack. Becallse more snow is deposi ted in the openings and less
in uncut forest, total storage on headwater basins is not changed.

2.
forest.
cutting.
and peak

Snowmelt in clearcut openings is more rapid than in the uncut
Streamflow is higher on the rising limb of hydrograph than before
When 50 percent of forest cut is in small openings, recession flows
flows are not changed appreciably.

3. In central Colorado when 40 percent of the watershed is occupied by
small openings, artnual water yields are increased by two inches. The decrease
in interception loss is almost compensated by the increase in evaporation loss
from snow surface. The recharge requi rement to the basin decreased by about
one inch and evapotranspiration during the growing season decreased by more
than 1.5 inches.

4. lI'ater yield increases averaged 3.5 inches due to timber cutting on
Fool Creek Watershed in Colorado. These runoff increases are tapering off
with time (I inch per 10 years, 1960-1970).

5. The pattern in which trees are cut determines whether or not runoff
will be increased. Streamflow increases are greatest when the forest is cut
in small openings. Water-yield increases are far less in case of clearcutting
when compared to patchcutting. II'hen the canopy density is reduced 50 percent
by selective cutting in spruce-fir forests on northerly aspects, water-yield
may actually be decreased.

(2) Forest ~mnagement for Increased Water Yield -- How useful in southenl
Alberta, by Charles R. Neill, Canadian Water Resources Journal, Vol. 5,
No.1, 1980.

The paper summarizes a study conducted for the Oldman Basin in Southern
Alberta and review of research results from the other regions of the \;orld.
The results of small basin studies are Slmunarized below based on Hibbert (35):

1. Reduct ion of forest
clearcutting or patchclltting.
50%).

cover generally increases \;ater )"ield, both for
Percentage increases are highly variable (5% to

2. The gain in yield declines as vegetation re-establishes, rapidly .,t
first and then more slowly.

1

-.~""""'~;T" ."..