FLOOD09816

• County: Statewide
• Basin: Statewide
• Title: Forest- Fire Devegetation and Drainage Basin Adjustments in Mountenous Terrain
• Date: 1/1/1977
• Prepared By: Department of Geology University of New Mexico
• Floodplain - Doc Type: Educational/Technical/Reference Information

.

Forest-Fire Devegetation and Basin Adjustments

After one year of field instrumentation. generalized relationships can be
drawn between the amount and location of erosion within a single watershed.
The amount of erosion is greater in the headwaters and near-mouth portions
of the watershed than in the mid-basin regions. Comparison of November
1978, measurements for each transect (headwater. mid-basin. and basin mouth)
exemplifies this relationship (fig. 6). This relationship held true throughout
the period of measurement except for the light-burn basin.. which was in-
fluenced by animal activity.

Seasonal Variations in Erosion

In October more erosion occurred in the Apache Springs watersheds than
in the Burnt Mesa drainage basins (table 4). Average erosion along each
transect was less than 1 mm in Burnt Mesa but averaged 3 mm in Apache
Springs. These differences in erosion are controlled. in part. by the rate
of destruction of the hydrophobic layer. Apache Springs watersheds have
steeper slopes (table 1), and therefore overland flow can attain greater
velocities. Consequently. most of the hydrophobic layers were removed from
the Apache Springs area. Longer time periods are needed to erode the

~
.
.
,
.
,
.

BURNT MESA STUDY AREA

.

I"'TENSE-BURN WATERSHED ~
--./ ----
//-----Y" --: .A
~ ./ '--<I
/

.c.

E
.5
is .
in
o .
'"
"'

HEADWATER TRANSECT
o MID. BASII'l TRANSECT
>l BASIN MOUTH TRANSECT

~OOERATE-BURN WATERSHED

.--/
---

I-
"'
z

.

M

.
,
.

1.IGHT.eURN WATERSHED

.

.

'1.0

,
o .. 0 I J
1977 I

FMAMJ.JASONO
TIME (MONTHS) 1978

Figure 6. SernU-logartthmic plots of seasonal variation in erosion for the
Burnt Mesa watersheds.

?no