General Technical Report
PSW-GTR-168-Web
Publications Related to Caspar Creek
Ingrid Morken1 and Robert R.
Ziemer2
1 Member, Americorps USA, The Watershed Stewards Project, c/o Pacific
Southwest Research Station, 802 N. Main Street, Fort Bragg, CA 95437.
2 Chief Research Hydrologist, USDA Forest Service, Pacific Southwest
Research Station, 1700 Bayview Drive, Arcata, CA 95521. (rrz7001@axe.humboldt.edu)
Albright, Jeffrey S. 1992. Storm runoff comparisons of
subsurface pipe and stream channel discharge in a small, forested watershed
in northern California. Arcata, CA: Humboldt State University; 118
p. M.S. thesis.
Pipe discharge, stream discharge, and rainfall were measured for
three winter storm seasons in the Caspar Creek watershed. Comparisons
of pipe discharge and stream discharge for 22 storm events
indicated that pipes respond dynamically to rainfall inputs. Pipes convey
a substantial volume of runoff from study swales.
Key Terms: pipeflow, storm runoff, subsurface flow
Anderson, H.W. 1960. Proposed program for watershed
management research in the lower conifer zone of
California. Tech. Paper 46. Berkeley, CA: Pacific Southwest Forest and Range Experiment
Station, Forest Service, U.S. Department of Agriculture; 21 p.
A 10-year program is proposed for California's Lower Conifer
Zone that establishes experimental watersheds in four commercial
timber areas: southern Sierra, northern Sierra, interior Douglas-fir,
and coastal redwood-Douglas-fir regions. Caspar Creek became
the experimental watersheds in coastal redwood-Douglas-fir region.
Key Terms: experimental watersheds
Anonymous. 1964. Second progress report 1963-64,
cooperative watershed management in the lower conifer zone of
California. Berkeley, CA: Pacific Southwest Forest and Range
Experiment Station, Forest Service, U.S. Department of Agriculture; 19 p.
Describes establishment and first year's data from the new
Caspar Creek Experimental Watersheds, including the stream habitat
study conducted by Dr. Kenneth Watt, University of California, Davis.
Key Terms: experimental watersheds, stream habitat
Anonymous. 1987. Caspar Creek: discovering how
watersheds respond to logging. Forestry Research West, August 1987.
Berkeley, CA: Pacific Southwest Forest and Range Experiment Station,
Forest Service, U.S. Department of Agriculture.
This pamphlet provides a historical overview of the Caspar
Creek watershed study, including results and future plans of the project.
The findings greatly illuminate the extent and nature of the
hydrologic impact, erosion, and stream sedimentation for a northern
California basin undergoing a "typical" logging operation.
Long-term investigations of logging effects on the Caspar Creek watershed
will provide forest managers, public policy makers, and private
enterprise an empirical basis on which to formulate sound logging practices.
Key Terms: streamflow, sedimentation, logging, roads,
cumulative watershed effects, fisheries
Anonymous. 1988. Caspar Creek: how a northwestern
California watershed responds to logging. [20-minute video.] San
Francisco, CA: Luba Productions. Available from: U.S. Forest Service
Video Library, 800-683-8366.
This video presents the hydrologic impacts of logging in the
northern California watershed of Caspar Creek from the beginning of the
Caspar Creek watershed study in 1962 to the ongoing research in 1988.
The effects of road building and logging on sedimentation,
streamflow, and cumulative effects are discussed as well as future studies
on fisheries.
Key Terms: sedimentation, streamflow, cumulative watershed
effects, fisheries, logging, roads
Baumann, R.W.; Bottorff, R.L. 1997. Two new species
of Chloroperlidae (Plecoptera) from
California. Great Basin Naturalist 57(4): 343-347.
Two new species in the family
Chloroperlidae (stoneflies) are described. One species,
Sweltsa pisteri, was initially identified
after collection from South Fork Caspar Creek. Detailed
illustrations, observations, and comparisons to similar species are provided.
Key Terms: stoneflies, biology, macroinvertebrates
Bottorff, R.L.; Knight, A.W. 1996. The effects of clearcut logging
on stream biology of the North Fork of Caspar Creek,
Jackson Demonstration State Forest, Fort Bragg, CA1986 to
1994. Unpubl. Final Rept. prepared for the Calif. Dept. of Forestry
and Fire Protection, Contract No. 8CA3802. Sacramento, CA. 177 p.
The objective of the North Fork Caspar Creek biological study was
to determine whether logging treatments (1989-1991) within
the drainage basin caused changes in three components of
stream structure and function: (1) the benthic macroinvertebrate
community, (2) leaf litter processing rates, and (3) the benthic algal
community. This report describes the results of 8 years of study (1987-1994) on
the stream biology of North Fork Caspar Creek, including three
pre-treatment years and five post-treatment years.
Key Terms: stream ecology, logging
Brown, David Lawrence. 1995. An analysis of transient flow
in upland watersheds: interactions between structure and
process. Berkeley, CA: University of California; 225 p. Ph.D. dissertation.
Field observations of responses of pore pressure to rain events at
two diverse experimental watersheds indicate that heterogeneous soil
and geologic materials affect storm runoff responses. The results of a
series of parametric simulations based on a physically based
numerical subsurface flow model suggest that significantly macroporous
soils may enhance the contribution of a soil horizon or geologic material
to hillslope discharge. Antecedent moisture conditions, channel
bank geometry, and lateral heterogeneities in soil hydraulic properties
affect the subsurface flow paths.
Key Terms: subsurface flow, storm runoff, modeling
Burns, J.W. 1970. Spawning bed sedimentation studies in
northern California streams. California Fish and Game 56(4): 253-270.
Changes in the size composition of spawning bed materials in
six coastal streams, including Caspar Creek, were monitored for 3 years
to determine the effects of logging on the habitat of silver salmon
(Coho), and trout (steelhead). Spawning bed composition in four test
streams changed after logging, roughly in proportion to the amount
of streambank disturbance. Sedimentation was greatest during
periods of road construction near streams and removal of debris from
streams, confirming the need for special measures to minimize erosion
during such operations.
Key Terms: sedimentation, logging, channel morphology, fisheries
Burns, J.W. 1971. The carrying capacity for juvenile salmonids in
some northern California streams. California Fish and Game 57(1): 44-57.
Standing crops of three species of juvenile salmonids were
examined in seven coastal streams [including Caspar Creek] to define the
natural carrying capacity of these streams, and to develop methods
of population comparison and prediction that could be used to
determine the effects of road construction and logging on salmon and
trout production. Biomass per unit of surface area was found to be the
best method of expressing carrying capacity. Not all streams
reached carrying capacity, and salmonid biomass was highly
variable, suggesting that it would be difficult to attribute a change in
carrying capacity under 50 percent to anything but natural variation.
Key Terms: fisheries, roads, logging
Burns, J.W. 1972. Some effects of logging and associated
road construction on northern California
streams. Transactions, American Fisheries Society 101: 1-17.
The effects of logging and associated road construction on
four California trout and salmonid streams were investigated from
1966 through 1969. This study included measurements of
streambed sedimentation, water quality, fish food abundance, and stream
nursery capacity. Sustained logging prolonged adverse conditions in
one stream and delayed stream recovery. Other effects of logging
on anadromous fish populations are discussed.
Key Terms: fisheries, sedimentation, logging, roads
Cafferata, P.H. 1984. The North Fork of Caspar Creek: a
cooperative venture between CDF and USFS. Jackson Demonstration
State Forest Newsletter, No. 15, August 1984. p. 1-2.
The California Department of Forestry (CDF) and the USDA
Forest Service (USFS) continue to be equal partners in implementing
the North Fork phase of the Caspar Creek Watershed Study. Parshall
flume sites and pumping samplers have been installed in the North Fork
to aid in measuring stream discharge and suspended sediment
load, respectively. The cooperative link of CDF and USFS provides a
broad, effective resource base for studying "cumulative effects" and
sediment transport mechanisms operating in a small logged watershed.
Key Terms: instrumentation, cumulative watershed
effects, sedimentation
Cafferata, P.H. 1987. Update on the Caspar Creek watershed
study. Jackson Demonstration State Forest Newsletter, No. 27,
October 1987. p. 1-4.
This article focuses on studies taking place in the North Fork of
Caspar Creek following clearcutting in selected sub-basins between 1989
and 1994. The primary study is on cumulative effects, and includes
the sediment impacts on the channel system that occur downstream
from the locations of the actual logging and are transmitted through
the stream system. Studies on channel morphology, biology of the
creek, and hillslope hydrology also are described.
Key Terms: cumulative watershed effects, channel morphology,
stream ecology, subsurface flow
Cafferata, Peter. 1990. Graduate theses produced from
research conducted on Jackson Demonstration State
Forest. Jackson Demonstration State Forest Newsletter, No. 36, January 1990. p. 4-8.
A primary goal for Jackson Demonstration State Forest (JDSF) is
to carry out research on the various aspects of forestry in the
redwood region. In this article, graduate theses produced from
research conducted on JDSF are cited and annotated. Research topics
include watersheds, soils, stream ecology, redwood ecology, silviculture,
forest entomology, and forest pathology.
Key Terms: redwood silviculture, watershed studies, stream
ecology, terrestrial biology, soils
Cafferata, Peter. 1990. Temperature regimes of small streams
along the Mendocino coast. Jackson Demonstration State
Forest Newsletter, No. 39, October 1990. p. 4-7.
Stream temperature has been measured in the Caspar Creek
drainage periodically over the past 25 years. Review of these data collected
from western Mendocino County illustrates much about the
temperature regimes of small coastal drainages, and how timber harvesting
affects them. This article gives a synopsis of these studies and
summarizes reasons for concern. Presented is a model currently in use by
the USDA Forest Service to predict changes in maximum
summer temperatures resulting from canopy reductions.
Key Terms: stream temperature, fisheries, logging
Cafferata, Peter H.; Spittler, Thomas E. 1998.
Logging impacts of the 1970's vs. the 1990's in the Caspar Creek
watershed. In: Ziemer, Robert R., technical coordinator. Proceedings of the conference
on coastal watersheds: the Caspar Creek story, 1998 May 6; Ukiah,
CA. Gen. Tech. Rep. PSW GTR-168. Albany, CA: Pacific
Southwest Research Station, Forest Service, U.S. Department of
Agriculture; 103-115.
The frequency of landslides greater than 76
m3 to date has not been substantially different between the clearcut units and the uncut
control subwatersheds for the North Fork of Caspar Creek. The volume
of sediment discharged by landslides to date has been about the same,
21 m3 ha-1 from the uncut units and 19
m3 ha-1 from the harvested
areas. Long-term monitoring will determine if these trends continue
with much larger stressing storm events. For perspective, the
largest landslide mapped in the North Fork watershed, a debris flow
that dammed the creek for thousands of years, was on the order
of 1,000,000 to 5,000,000 m3 over three orders of magnitude
larger than the largest landslide observed during the study.
Key Terms: landslides, slope stability, logging, roads,
sediment, geomorphology
Cafferata, P.; Walton, K.; Jones, W. 1989. Coho salmon
and steelhead trout of JDSF. Jackson Demonstration State
Forest Newsletter, No. 32, January 1989. p. 1-7.
Spawning and rearing habitat for anadromous fish is the
dominant use of Jackson Demonstration State Forest's (JDSF) many miles
of streams. Both Coho (silver) salmon and steelhead migrate from
the ocean up the rivers to spawn. This article summarizes life histories
of Coho salmon and steelhead and describes the fisheries activities
on JDSF. Fisheries activities on Caspar Creek include downstream
migrant studies and standing crop surveys.
Key Terms: fisheries, stream restoration, stream ecology
Dahlgren, Randy A. 1998. Effects of forest harvest
on biogeochemical processes in the Caspar Creek
Watershed. Unpubl. Draft Final Rept. prepared for the Calif. Dept. of Forestry and
Fire Protection. Agreement No. 8CA17039. Sacramento, CA. 151 p.
Forest harvest practices are often implicated as having adverse
impacts on sensitive aquatic communities and on the long-term
sustainability of forest ecosystems. The primary purpose of this research was
to examine the effects of forest harvest and post-harvest
management practices on biogeochemical processes. Results provide information
to understand the complex interactions that occur in nutrient
cycling processes at the ecosystem scale.
Key Terms: biogeochemical processes, logging, nutrient cycling,
water quality
Dahlgren, Randy A. 1998. Effects of forest harvest on
stream-water quality and nitrogen cycling in the Caspar Creek
watershed. In: Ziemer, Robert R., technical coordinator. Proceedings of
the conference on coastal watersheds: the Caspar Creek story,
1998 May 6; Ukiah, CA. Gen. Tech. Rep. PSW GTR-168. Albany,
CA: Pacific Southwest Research Station, Forest Service, U.S.
Department of Agriculture; 45-53.
The effects of forest harvest on stream water quality and
nitrogen cycling were examined for a redwood/Doug fir ecosystem in the
North Fork, Caspar Creek experimental watershed. Stream water
samples were collected from treated (e.g., clearcut) and reference
(e.g., non-cut) watersheds, and from various locations downstream from
the treated watersheds to determine how far the impacts of these
practices extended. Additionally, a detailed nutrient cycling study
was performed in a clearcut and reference watershed to gain insights
into changes in nitrogen cycling following harvesting activities.
Key Terms: streamflow, cumulative watershed effects, nutrient
cycling, logging, nitrogen, calcium
Dorn, R. 1969. Evaluation of air and water temperatures on
Caspar Creek from 1965-1968. Unpubl. Rept. Cooperative Fisheries
Unit, Humboldt State University, Arcata, CA. 17 p.
Key Terms: watershed studies, temperature, roads
Duan, J.; Ziemer, R.R.; Grant, G.E. 1997. Hydrologic responses
of large drainage to clearcutting: a modeling
perspective. EOS, Transactions, American Geophysical Union 78(46): F314.
Hydrologic responses of watersheds at the 100- to
1000-km2 scale using a river routing model based on knowledge derived from
paired-watershed studies at the 10- to 100-ha scale are presented.
Primary results demonstrate both scale-independent and dependent
changes in runoff volume, peak flow size, and timing in response to
various scenarios of cutting pattern and proportion of area cut.
Key Terms: watershed studies, storm runoff, peak flow, logging
Eads, R.E. 1991. Controlling sediment collection with data
loggers. In: Fan, S.; Kuo, Y.H., eds. Fifth Federal Interagency
Sedimentation Conference Proceedings, 1991 March 18-21, Las Vegas, NV.
Washington, DC: Federal Energy Regulatory Commission; 2-41 to 2-48.
Sampling efficiency in many types of hydrologic data collection can
be improved using a programmable data logger. Low-power
requirements, ease of programming, and the increased flexibility of connecting
multiple sensors also can improve data collection in remote locations.
Key Terms: instrumentation, sampling, streamflow,
suspended sediment
Eads, Rand E.; Boolootian, Mark R. 1985. Controlling
suspended sediment samplers by programmable calculator and
interface circuitry. Res. Note PSW-376. Berkeley, CA: Pacific
Southwest Forest and Range Experiment Station, Forest Service,
U.S. Department of Agriculture; 8 p.
Automatic pumping samplers can improve the collection of data
on suspended sediment when operated at fixed time intervals.
A programmable calculator controls the collection of pumped
suspended sediment samples and records streamflow data. Wiring
schematic, component list, and program listing are included.
Key Terms: instrumentation, sampling, suspended
sediment, streamflow
Eads, Rand E.; Boolootian, Mark R; Hankin, Steven C.,
inventors; United States of America, assignee. 1987.
Means and method of sampling flow related variables from a waterway in an
accurate manner using a programmable
calculator. U.S. patent 4,660,422. Apr. 28. 9 p. Int. Cl.4 G01N 1/44.
A programmable calculator connected to a pumping sampler by
an interface circuit board runs a sediment-sampling program
stored therein. Suspended sediment sample collection is controlled by
a Selection At List Time (SALT) scheme in which the probability
of taking a sample is proportional to its estimated contribution to
total sediment discharge, or according to accumulated predicted
sediment weight. Stage height is also measured and is recorded according to
a set scheme.
Key Terms: instrumentation, sampling, suspended
sediment, streamflow
Eads, Rand E.; Thomas, Robert B. 1983. Evaluation of a
depth proportional intake device for automatic pumping
samplers. Water Resources Bulletin 19(2): 289-292.
A depth proportional intake boom for portable pumping
samplers was used to collect suspended sediment samples in two coastal
streams for three winters. This equipment maintains the intake nozzle at
the same proportion of water depth regardless of stage. Compared to
data taken with depth integrated hand samples, the data taken by
pumped samplers with boom-mounted intakes showed higher
concentrations. Results suggested that cross-sectional sampling can give high
precision with proper placement and calibration of a boom-mounted intake.
Key Terms: instrumentation, sampling, suspended
sediment, streamflow
Fisher, Jason C. 1997. A one-dimensional model of
subsurface hillslope flow. Unpublished Final Report. Redwood
Sciences Laboratory, Pacific Southwest Research Station, USDA
Forest Service, Arcata, CA. 62 p.
A one-dimensional, finite difference model of saturated
subsurface flow within a hillslope was developed. The model uses
rainfall, elevation data, a hydraulic conductivity, and a storage coefficient
to predict the saturated thickness in time and space. The model
was tested against piezometric data collected in a swale located in
the headwaters of the Caspar Creek watershed and was limited in its
ability to reproduce historical piezometric responses.
Key Terms: hillslope hydrology, subsurface flow, modeling
Graves, D.S.; Burns, J.W. 1970. Comparison of the yields
of downstream migrant salmonids before and after logging and
road construction on the South Fork Caspar Creek, Mendocino
County. Inland Fisheries Admin.: Rept. 70-3. 11 p. Sacramento, CA:
Calif. Dept. of Fish and Game.
Yields of juvenile steelhead and silver (Coho) salmon emigrants
were compared in the South Fork of Caspar Creek, before and after
the construction of a logging road along the stream. Numbers,
lengths, and age-class structures of the juvenile salmonids were compared.
The possible effects of stream disturbance on the size of migrants were
also investigated.
Key Terms: logging, roads, fisheries, stream ecology
Hardison, Karen D. 1982. Effects of timber harvesting on the lag time
of a Caspar Creek watershed...a study in
progress. Jackson Demonstration State Forest Newsletter, No. 8, September 1982. p 1-3.
In this study, two measurements of lag time are analyzed for
each storm in the Caspar Creek Watershed. One is the time
separation between the center of mass of rainfall and the center of mass of
total runoff, the other is the time separation between the center of mass
of rainfall and the center of mass of rising limb runoff. Analysis of
any change in lag time after roadbuilding and logging will indicate
changes in the processes involved in stormflow at this site.
Key Terms: storm runoff, logging, streamflow, roads
Harvey, B.C.; Nakamoto, R.J. 1996. Effects of steelhead density
on growth of Coho salmon in a small coastal California
stream. Transactions, American Fisheries Society 125: 237-243.
Weight change in age-0+ Coho salmon
(Oncorhynchus kisutch) at about natural density was negatively related to the density of
juvenile steelhead (O. mykiss) in a 6-week experiment conducted in
July-August 1993 in the North and South forks of Caspar Creek. In the North
Fork, Coho salmon weight change was positive in zero density
steelhead treatments, zero in 1X treatments, and negative in 2X
treatments. Coho salmon weight change in the South Fork was less favorable
than in the North Fork but also negatively related to steelhead density.
Key Terms: fisheries, stream ecology
Harvey, Bret C.; Nakamoto, Rodney J. 1997.
Habitat-dependent interactions between two size-classes of juvenile steelhead in a
small stream. Canadian Journal of Fisheries and Aquatic Sciences 54(1): 27-31.
The presence of small steelhead influenced the growth of larger
juvenile steelhead during a 6-week experiment conducted in North Fork
Caspar Creek in 1994. In fenced replicate deep-stream sections in this
small stream, growth of the larger steelhead was greater in treatments
in which small steelhead constituted half of the total biomass of fish
than in treatments with an equal biomass composed entirely of larger
fish. The advantage of large body size in intraspecific interactions
among steelhead does not exist in all types of habitat, and
interactions between the two size-classes may contribute to lower abundance
of large juveniles in streams where aggradation reduces water depth.
Key Terms: fisheries, stream ecology
Henry, Norm. 1991. Using global positioning system
technology for watershed mapping in Caspar
Creek. Jackson Demonstration State Forest Newsletter, No. 43, October 1991. p. 4-6.
Global positioning system (GPS) technology is described, and GPS
use in the Caspar Creek Watershed is demonstrated. The
cumulative effects study and several other studies of the North Fork phase
require accurate mapping and periodic map updating of the
watershed features and disturbances. The watershed features surveyed using
GPS technology are now accurately located in relation not only to
other objects in the watershed but also to a regional and global frame
of reference.
Key Terms: instrumentation, mapping
Henry, Norm. 1998. Overview of the Caspar Creek watershed
study. In: Ziemer, Robert R., technical coordinator. Proceedings of
the conference on coastal watersheds: the Caspar Creek story,
1998 May 6; Ukiah, CA. Gen. Tech. Rep. PSW GTR-168. Albany,
CA: Pacific Southwest Research Station, Forest Service, U.S.
Department of Agriculture; 1-9.
This paper describes the history, site characteristics, major
events, equipment, and sampling systems used during the South Fork
and North Fork phases of the Caspar Creek study from 1962 through 1998.
Key Terms: paired watersheds, research, streamflow,
sediment, precipitation
Henry, N.; Sendek, K. 1985. Caspar Creek Watershed
StudyNorth Fork Phase, Jackson Demonstration State Forest, Status and
Plans, 1983-1990. Calif. Forestry Note No. 96. Sacramento, CA:
Calif. Dept. of Forestry and Fire Protection; 9 p.
The North Fork phase of the Caspar Creek Watershed Study for
1983 to 1990 uses an extensive network of flumes with pumping samplers
to monitor the impacts of clearcutting a portion of the North
Fork. Principal objectives are to identify sediment sources, and evaluate
the magnitude and movement of sediment through the watershed.
A "cumulative" effects hypothesis tested as clearcutting progresses
from the headwaters to the weir.
Key Terms: suspended sediment, streamflow, sampling,
cumulative watershed effects, logging, roads
Hess, Lloyd J. 1969. The effects of logging road construction
on insect drop into a small coastal
watercourse. Arcata, CA: Humboldt State University; 58 p. M.S. thesis.
The purpose of this paper is to relate logging practices to
fish management by ascertaining the effect of logging road
construction on the drop of insects into a stream. On the South Fork of
Caspar Creek, the number of insects falling into the stream greatly
increased after a logging road was built. The family
Chironomidae showed the most significant increase of the families studied.
Key Terms: stream ecology, roads, logging, fisheries
Hopkins, Walt; Bowden, Kenneth L. 1962. First progress report,
1961-1962, cooperative watershed management in the lower conifer zone
of California. Berkeley, CA: Pacific Southwest Forest and Range
Experiment Station, Forest Service, U.S. Department of Agriculture; 10 p.
The Caspar Creek study, "Study 2-1, a study of logging effects
upon streamflow, sedimentation, fish life and fish habitat in the north
coast redwood-Douglas-fir forest type Jackson State Forest, Fort
Bragg, California" was one of the first studies undertaken by the new
Lower Conifer research project.
Key Terms: experimental watersheds
Kabel, C.S.; German, E.R. 1967. Caspar Creek study
completion report. Marine Resources Branch Administrative Report No.
67-4. Sacramento, CA: The Resources Agency of Calif. Dept. of Fish
and Game; 27 p.
This study evaluated the effects of logging on the stream and
its population of silver (Coho) salmon and steelhead trout. Changes
in anadromous fish production were measured through counts
of upstream and downstream migrants. Existing habitat in the
stream was surveyed as well. Measurement of anadromous fish
production was difficult owing to technical problems.
Key Terms: fisheries, stream ecology, logging
Keppeler, Elizabeth T. 1986. The effects of selective logging on
low flows and water yield in a coastal stream in northern
California. Arcata, CA: Humboldt State University; 137 p. M.S. thesis.
Using a low flow season defined as a function of
antecedent precipitation, streamflow data for a 21-year period were analyzed
to determine the effects of selective tractor on the volume, timing,
and duration of low flows, and annual water yield. Significant increases
in streamflow were detected for both the annual period and the low
flow season. Logging factors were found to be the most influential
variables in describing flow differences between the control and
treated watersheds. The enhancement of annual yield was well correlated
to the percent of the watershed area converted to roads, landings,
and skid trails.
Key Terms: streamflow, logging, roads
Keppeler, Elizabeth T. 1998. The summer flow and water
yield response to timber harvest. In: Ziemer, Robert R.,
technical coordinator. Proceedings of the conference on coastal
watersheds: the Caspar Creek story, 1998 May 6; Ukiah, CA. Gen. Tech.
Rep. PSW GTR-168. Albany, CA: Pacific Southwest Research
Station, Forest Service, U.S. Department of Agriculture; 35-43.
Selection/tractor logging of the South Fork increased annual yield by
a maximum of 2053 m3ha-1 during the seventh water year after
harvest began. Increased yields were observed beginning the second
post-harvest year and averaged 15 percent or 932
m3ha-1. Following clearcut logging 50 percent of the North Fork watershed, annual yield
increased by as much as 1032
m3ha-1 eight years post-logging and averaged
15 percent or 608 m3ha-1 beginning in the second post-harvest
year. Summer flow increases were evident on the South Fork for seven
years after logging. Minimum summer flow discharge increases averaged
38 percent after the South Fork selection logging and 148 percent
after the North Fork harvest and site preparation.
Key Terms: streamflow, soil moisture, summer flow, logging
Keppeler, Elizabeth T.; Brown, David. 1998. Subsurface
drainage processes and management impacts. In: Ziemer, Robert
R., technical coordinator. Proceedings of the conference on
coastal watersheds: the Caspar Creek story, 1998 May 6; Ukiah, CA.
Gen. Tech. Rep. PSW GTR-168. Albany, CA: Pacific Southwest
Research Station, Forest Service, U.S. Department of Agriculture; 25-34.
Storm-induced streamflow in forested upland watersheds is linked
to rainfall by transient variably-saturated flow through several
different flow paths. In the absence of exposed bedrock, shallow
flow-restrictive layers, or compacted soil surfaces, virtually all of the infiltrated
rainfall reaches the stream as subsurface flow. Subsurface runoff can
occur within micropores (voids between soil grains), various types
of macropores (structural voids between aggregates, plant and
animal-induced biopores), and through fractures in weathered and
consolidated bedrock. In addition to generating flow through the subsurface,
transient rain events can also cause large increases in fluid pressures within
a hillslope. If pore pressures exceed stability limits of soils and
shallow geologic materials, landslides and debris flows may result.
Key Terms: soil moisture, pipeflow, saturated flow,
landslide, macropore
Keppeler, E.T.; Cafferata, P.H. 1991. Hillslope hydrology
research at Caspar Creek. Jackson Demonstration State Forest
Newsletter, No. 41, April 1991. p. 4-8.
The latest technology is used for documenting variations
in groundwater levels and soil moisture conditions from season to
season and through storm events. Subsurface soil pipes are also monitored
to observe changes in water movement.
Key Terms: hillslope hydrology, subsurface flow, logging, roads
Keppeler, Elizabeth T.; Ziemer, Robert R. 1990.
Logging effects on streamflow: water yields and summer low flows at Caspar Creek
in northwestern California. Water Resources Research 26(7): 1669-1679.
Streamflow data for a 21-year period were analyzed to determine
the effects of selective tractor harvesting of second-growth Douglas-fir
and redwood forest on the volume, timing, and duration of low flows
and annual water yield in northwestern California. The flow response
to logging was highly variable. Significant increases in streamflow
were detected for both the annual period and the low-flow season.
Key Terms: streamflow, logging, roads
Keppeler, Elizabeth T.; Ziemer, Robert R.; Cafferata, P.H.
1994. Changes in soil moisture and pore pressure after harvesting
a forested hillslope in northern California. In: Marston,
R.A.; Hasfurther, V.R., eds. Effects of human-induced changes
on hydrologic systems; 1994 June 26-29; Jackson Hole, WY.
Herndon, VA: American Water Resources Association; 205-214.
From 1987 to 1993, soil moisture conditions were measured along
a 0.83-ha zero-order swale using pressure transducers connected to
a digital data logger. In August 1989, the 100-year-old
second-growth forest in the swale was felled, and logs were removed by cable
yarding. Increases in peak piezometric levels and soil moisture were
observed after logging. After logging, soil pipes continued to efficiently
route surplus stormflows through an existing piping network. No
slope failures were observed.
Key Terms: hillslope hydrology, soil moisture, pipeflow, storm
runoff, logging
Kinerson, D.; Dietrich, William. 1990. Bed surface response
to sediment supply. Berkeley, CA: Dept. of Geology and
Geophysics, University of California; 420 p.
Land use changes in watersheds often lead to increased
sediment supply to streams and to reduced habitat quality for the fish that live
in these streams. There are three separable components to this land
use problem: (1) the relationship between management practices
and sediment yield, (2) the relationship between sediment supply and
the stream channel morphology and dynamics, and (3) the
relationship between sediment load and fish productivity. This study was
designed in part to quantify these relationships in order to predict how
changes in sediment supply will affect stream habitat.
Key Terms: sedimentation, stream ecology, channel
morphology, bedload
Kopperdahl, F.R.; Burns, J.W.; Smith, G.E. 1971.
Water quality of some logged and unlogged California
streams. Inland Fisheries Administrative Rept. No. 71-12. Sacramento, CA: Calif. Dept.
of Fish and Game; 19 p.
Water quality was monitored in 1968 and 1969 in six coastal
streams in northern California, four of which were subjected to logging
and/or road building (among them South Fork Caspar Creek), while the
others remained undisturbed (including North Fork Caspar Creek).
The purposes of this study were to characterize the water quality of
the streams, to determine whether the logging and road
construction drastically altered water quality, and to collect data on water
quality that could be tested for predicting stream carrying capacities
for salmonids. Conditions were generally suitable for salmonids
during and after the logging.
Key Terms: water quality, fisheries, logging, roads
Krammes, J.S.; Burns, D.M. 1973. Road construction on
Caspar Creek watersheds a 10-year progress
report. Res. Paper PSW-93. Berkeley, CA: Pacific Southwest Forest and Range
Experiment Station, USDA Forest Service; 10 p.
Measured suspended sediment yields increased by four fold during
the first winter after right-of-way clearing, road building, and
bridge construction; subsequent winter yields were not as excessive.
Other impacts of the road implementation include increased
water temperature, decreased young-of-the-year fish populations,
and changes in composition of streambed particle size.
Key Terms: roads, logging, streamflow, sedimentation, fisheries
Lewis, J. 1991. An improved bedload
sampler. In: Fan, S.; Kuo, Y.H., eds. Fifth Federal Interagency Sedimentation
Conference Proceedings, 1991 March 18-21, Las Vegas, NV. Washington,
DC: Federal Energy Regulatory Commission; 6-1 to 6-8.
Improvements upon the Birkbeck bedload sampler were
implemented in the North Fork of Caspar Creek, a gravel-bedded stream.
Bedload sediment falls through a slotted plate covering a
0.125-m3 steel box set within a formed concrete pit in the streambed. In two seasons
of experimentation, the pillow and hydraulic and mechanical linkages
of the Birkbeck-like sampler were replaced with an electronic load
cell, resulting in more trouble-free operation, greater precision,
and reduced background noise.
Key Terms: bedload, sediment, instrumentation, sampling
Lewis, Jack. 1996. Turbidity-controlled suspended
sediment sampling for runoff-event load
estimation. Water Resources Research 32(7): 2299-2310.
For estimating suspended sediment concentration (SSC) in
rivers, turbidity is generally a much better predictor than water
discharge. Measurements of SSC and turbidity were collected at
10-minute intervals from five storm events in a small, mountainous
watershed (Caspar Creek) that exports predominantly fine sediment.
Samples were selected from each storm's record, and event loads were
estimated by predicting SSC from regressions on turbidity. Using simple
linear regression, loads were estimated with root mean square
errors consistently lower than those of sediment rating curve estimates
based on the same samples.
Key Terms: suspended sediment, turbidity, storm runoff, sampling
Lewis, Jack. 1997. Changes in storm peak flows after clearcut
logging. EOS, Transactions, American Geophysical Union 78(46): F314.
Streamflow in a Caspar Creek watershed was monitored at 13
locations before and after 50 percent of the watershed was logged, primarily
by clearcutting. The logarithm of unit area peak flow was
statistically modeled as a function of control watershed peak flow, proportion
of watershed cut, antecedent wetness, and time since logging.
The logarithm of unit area peak flow was found to vary linearly with
the proportion cut, the slope decreasing with increasing
antecedent precipitation. Peak flow increases are attributed to loss
of evapotranspiration and interception in the treated watersheds.
Key Terms: storm runoff, peak flow, logging
Lewis, Jack. 1998. Evaluating the impacts of logging activities
on erosion and sediment transport in the Caspar Creek
watersheds. In: Ziemer, Robert R., technical coordinator. Proceedings of
the conference on coastal watersheds: the Caspar Creek story,
1998 May 6; Ukiah, CA. Gen. Tech. Rep. PSW GTR-168. Albany,
CA: Pacific Southwest Research Station, Forest Service, U.S.
Department of Agriculture; 55-69.
Suspended sediment has been sampled at both the North and
South Fork weirs since 1963, and at 13 tributary locations in the North
Fork since 1986. In the most conservative treatment of the data,
suspended loads increased by 212 percent over the total predicted for a
6-year period commencing with the onset of logging in hydrologic year
1971. When the roles of the watersheds were reversed and the same
analysis repeated to evaluate harvesting in the North Fork under
California Forest Practice Rules in the 1990's, no significant increase was
found at NFC in either annual suspended or bed load. Using a more
sensitive analysis, for the 7-year period commencing with the onset of
logging the North Fork , the sum of the suspended storm loads was 89
percent higher than that predicted for the undisturbed condition.
Key Terms: streamflow, suspended sediment, bedload,
cumulative watershed effects, logging, roads
Lewis, Jack; Eads, Rand. 1996. Turbidity-controlled
suspended sediment sampling. Watershed Management Council
Newsletter 6(4): 1, 4-5.
In Caspar Creek, turbidity has been measured for
estimating suspended sediment concentration (SSC). Results indicate
that turbidity is generally a better predictor of SSC than water
discharge. Turbidity also provides a more detailed picture of sediment
transport than is normally available.
Key Terms: turbidity, suspended sediment, sampling, instrumentation
Lisle, T.E. 1979. The Caspar Creek Experimental
Watershed. In: Guidebook for a field trip to observe natural and
management-related erosion in Franciscan Terrane of northern
California. Cordilleran Section of the Geological Society of America, 1979
April 9-11; San Jose, CA. Menlo Park, CA: Geological Society of
America; XIV-1 to XIV-8.
This paper offers an overview of the Caspar Creek
Experimental Watershed, including the project history, interpretations of the
data, and future plans. Effects of logging and road construction
on streamflow, erosion, and sedimentation are reported and discussed.
Key Terms: geology, streamflow, erosion, sedimentation, logging, roads
Lisle, T.E. 1989. Sediment transport and resulting deposition
in spawning gravels, north coastal California. Water
Resources Research 25(6): 1303-1319.
To relate sedimentation of spawning gravel beds to
sediment transport, infiltration of fine sediment (<2 mm in diameter) into
clean gravel beds, distribution of bed material size, scour-fill depths,
and sediment transport during 10 storm flow events were measured
in three streams of north coastal California. Great temporal and
spatial variation in sedimentation in these streams suggests that
individual storms of moderate size pose a threat to eggs in many but not all
areas selected by fish for spawning.
Key Terms: sediment transport, bedload, fisheries
Lisle, Thomas E.; Napolitano, Michael. 1998.
Effects of recent logging on the main channel of North Fork Caspar
Creek. In: Ziemer, Robert R., technical coordinator. Proceedings of
the conference on coastal watersheds: the Caspar Creek story,
1998 May 6; Ukiah, CA. Gen. Tech. Rep. PSW-GTR-168. Albany,
CA: Pacific Southwest Research Station, Forest Service, U.S.
Department of Agriculture; 81-85.
The response of the mainstem channel of North Fork Caspar Creek
to recent logging is examined by time trends in bed load yield, scour
and fill at resurveyed cross sections, and the volume and
fine-sediment content of pools. Changes in bed load yield were not detected despite
a strong correlation between total scour and fill and annual
effective discharge, perhaps because changes in stormflows were modest.
The strongest responses are an increase in sediment storage and
pool volume, particularly in the downstream portion of the channel along
a buffer zone, where large woody debris (LWD) inputs are high.
Key Terms: sediment, bedload, large woody debris logging, pool volume
Maahs, Michael; Gilleard, Jim. 1994. An evaluation of
rehabilitation efforts based on carcass recovery and spawning
activity. Anadromous salmonid resources of Mendocino County coastal
and inland rivers. Final Report, August 1994. Sacramento, CA:
Calif. Dept. of Fish and Game; 60 p.
To evaluate the effectiveness of salmon-restoration efforts,
spawning surveys were conducted in Mendocino County streams
(including Caspar Creek) in 1991-1992 and in 1990-1991. Restoration
activities were shown to be related to salmon production in several ways.
Key Terms: fisheries, stream ecology, stream restoration
Messer, Dean F.; Donaldson, Catherine L.; Parker, Michael
S.; Knight, Allen W. 1994. Effects of clear-cut logging practices
on benthic communities of the North Fork Caspar Creek
Watershed, Jackson State Demonstration Forest: Interim Report, Spring
1987 to Spring 1992. Land, Air, and Water Resources Paper No.
100024. Davis, CA: University of California; 28 p.
The goal of this research has been to determine whether changes
in physical processes related to clearcut logging are translated
into changes in the structure and function of in-stream floral and
faunal assemblages. This study obtained considerable data on
benthic macroinvertebrate densities, relative abundance of common taxa
and functional feeding groups, litter decomposition rates and
benthic macroinvertebrates inhabiting leaf litter accumulations, and
benthic algal standing crop and taxonomic structure at several sites
along North Fork Caspar Creek. Although this study did uncover
significant changes in several parameters, the specific reasons (drought or
logging effects) for such changes remain unclear.
Key Terms: sedimentation, stream ecology, logging
Morken, Ingrid; Ziemer, Robert R. 1998. Publications related
to Caspar Creek. In: Ziemer, Robert R., technical
coordinator. Proceedings of the conference on coastal watersheds: the
Caspar Creek story, 1998 May 6; Ukiah, CA. Gen. Tech. Rep.
PSW-GTR-168. Albany, CA: Pacific Southwest Research Station, Forest
Service, U.S. Department of Agriculture; 137-149.
Annotated bibliography of 107 papers produced during 36 years
of research in the Caspar Creek Experimental Watershed.
Key Terms: paired watersheds, bibliography, monitoring,
land management, resource issues
Nakamoto, Rodney. 1998. Effects of timber harvest on aquatic
vertebrates and habitat in the North Fork Caspar
Creek. In: Ziemer, Robert R., technical coordinator. Proceedings of the conference on
coastal watersheds: the Caspar Creek story, 1998 May 6; Ukiah, CA. Gen.
Tech. Rep. PSW-GTR-168. Albany, CA: Pacific Southwest Research
Station, Forest Service, U.S. Department of Agriculture; 87-95.
An increase in large woody debris volume resulting from blowdown
in the buffer zone following timber harvest increased the availability
of pools and changed channel sediment storage characteristics.
These changes suggest that yearling steelhead, Coho, and Pacific
giant salamanders may benefit via increased living space and
increased feeding efficiency.
Key Terms: aquatic vertebrates, steelhead, Coho, salamander,
habitat, riparian
Napolitano, Michael Brent. 1996. Sediment transport and
storage in North Fork Caspar Creek, Mendocino County, California:
water years 1980-1988. Arcata, CA: Humboldt State University; 148
p. M.S. thesis.
A sediment budget for mainstem North Fork Caspar Creek
was developed for water years 1980-1988 to evaluate controls on
sediment storage changes. Sediment budget findings, Caspar Creek
logging history, and research on large woody debris (LWD) were
reviewed together to evaluate persistence of historical logging
impacts. Comparison of LWD loading on North Fork Caspar Creek to
similar streams in old-growth redwood basins suggests that this creek may
not have recovered from 19th-century logging.
Key Terms: sedimentation, large woody debris, logging
Napolitano, Michael. 1998. Persistence of historical logging
impacts on channel form in mainstem North Fork Caspar
Creek. In: Ziemer, Robert R., technical coordinator. Proceedings of the conference
on coastal watersheds: the Caspar Creek story, 1998 May 6; Ukiah,
CA. Gen. Tech. Rep. PSW-GTR-168. Albany, CA: Pacific
Southwest Research Station, Forest Service, U.S. Department of
Agriculture; 97-101.
The old-growth redwood forest of Caspar Creek was clearcut
between 1864 and 1904. Transportation of logs was by splash dam in
the headwaters. Water stored behind the dam was released during
large storms to sustain log drives. Before log drives could be conducted,
all obstructions, including large woody debris (LWD) jams were
removed from the channel. Comparison of present-day LWD loading on
North Fork Caspar Creek (24 kg m2) to physically similar streams in
old-growth redwood basins (49 to 268 kg
m2) suggests that LWD loading and stability were greatly diminished by historical logging
activities and change to second-growth cover.
Key Terms: historic logging, large woody debris, stream
channel, redwood
Napolitano, Michael; Jackson, Francis; Cafferata, Peter. 1989.
A history of logging in the Caspar Creek
basin. Jackson Demonstration State Forest Newsletter, No. 33, April 1989. p. 4-7.
This article traces the history of logging in the Caspar Creek
basin since the time of its first European settler, Siegrid Caspar, who was
a trapper near the mouth of Caspar Creek before 1860. In 1860
the Caspar Lumber Company purchased 5,000 acres of forested terrain
in the Caspar Creek basin. By 1890, logging had been completed
over most of the watershed with the help of crib dams, skid (or
corduroy) roads, and steam donkeys. The tramway, crib dam, corduroy
roads, and other historic artifacts of early logging days are easily observed
in the North Fork basin today.
Key Terms: history, logging
O'Connor, Matthew D.; Ziemer, Robert R. 1989.
Coarse woody debris ecology in a second-growth
Sequoia sempervirens forest stream. In: Abell, Dana L., technical coordinator. Proceedings
of the California Riparian Systems Conference:
protection, management, and restoration for the 1990s; 1988 September
22-24; Davis, CA. Gen. Tech. Rep. PSW-110. Berkeley, CA:
Pacific Southwest Forest and Range Experiment Station, Forest
Service, U.S. Department of Agriculture; 165-171.
Coarse woody debris (CWD) volume, species, and input
mechanisms were inventoried in North Fork Caspar Creek to assess rates
of accumulation and dominant sources of CWD in a 100-year-old
second-growth redwood forest. CWD accumulation in the active
stream channel and in pools was studied to identify linkages between
the forest and fish habitat.
Key Terms: coarse woody debris, channel morphology, stream ecology
Parker, Michael. 1991. North Fork Caspar Creek stream
biology study. Jackson Demonstration State Forest Newsletter, No.
43, October 1991. p. 1-3.
Since spring 1987, a group of aquatic ecologists have been
studying the effects of timber harvesting on stream biota in North Fork
Caspar Creek to determine how current logging practices within a
relatively undisturbed second-growth redwood forest influence the
distribution and abundance of algae and invertebrates. Important invertebrates
in North Fork Caspar Creek include mayflies, true flies, caddisflies,
and stoneflies. Preliminary results indicate that small, relatively
fast-growing mayflies and midges are more abundant after
logging, probably owing to increases in algae abundance.
Key Terms: stream ecology, logging
Pearce, Richard B. 1993. Caspar Creek: discovering how
watersheds respond to logging. Berkeley, CA: Pacific Southwest
Research Station, USDA Forest Service; 6 p. (Revised from August 1987
issue of Forestry Research West).
This pamphlet provides a historical overview of the Caspar
Creek watershed study, including results and future plans of the project.
The findings have illuminated the extent and nature of the
hydrologic impacts of logging operations "typical" for the time period.
Key Terms: streamflow, sedimentation, logging, roads,
cumulative watershed effects, fisheries
Pert, Heather Anne. 1993. Winter food habits of coastal
juvenile steelhead and Coho salmon in Pudding Creek, northern
California. Berkeley, CA: University of California; 65 p. M.S. thesis.
Diets of juvenile Coho salmon and steelhead and the composition
and density of drift were examined from November 1990 to April 1991
in the coastal stream Pudding Creek located to the north of the
Caspar Creek drainage. Using some Caspar Creek data, drift
density, antecedent precipitation, and water temperature were correlated
to steelhead stomach fullness, whereas stomach fullness of Coho
salmon was generally low and not well correlated with any of the
variables measured. Winter floods may be important for food supply
and sustaining salmonid growth and condition at these sites.
Key Terms: fisheries, storm runoff, stream ecology
Reid, Leslie M. 1998. Cumulative watershed effects: Caspar
Creek and beyond. In: Ziemer, Robert R., technical
coordinator. Proceedings of the conference on coastal watersheds: the
Caspar Creek story, 1998 May 6; Ukiah, CA. Gen. Tech. Rep.
PSW-GTR-168. Albany, CA: Pacific Southwest Research Station,
U.S. Department of Agriculture; 117-127.
Cumulative effects are the combined effects of multiple activities,
and watershed effects are those which involve processes of water
transport. Past approaches to evaluating and managing cumulative
watershed effects included the use of mechanistic predictive models, indices
of land-use intensity, and open-ended analysis. None has yet
proved successful for averting cumulative impacts. Approaches being
discussed now include requirements for "zero net increase" of sediment, linkage
of planned activities to mitigation of existing problems, use of
more protective best management practices, and adoption of thresholds
either for land-use intensity or for impact level. Future impact analysis
methods probably will be based on strategies for watershed analysis.
Key Terms: cumulative effects, erosion, sediment,
watershed, predictive models
Reid, Leslie M.; Hilton, Sue. 1998. Buffering the
buffer. In: Ziemer, Robert R., technical coordinator. Proceedings of the conference
on coastal watersheds: the Caspar Creek story, 1998 May 6; Ukiah,
CA. Gen. Tech. Rep. PSW-GTR-168. Albany, CA: Pacific
Southwest Research Station, Forest Service, U.S. Department of
Agriculture; 71-80.
Riparian buffer strips help to sustain aquatic ecosystems and
to protect downstream resources and values in forested areas,
but controversy persists over how wide a buffer strip is
necessary. Although most tree-fall-related sediment and woody debris inputs
to Caspar Creek are generated by tree fall within a tree's height of
the channel, trees falling from upslope of the contributing tree
trigger about 30% of those tree falls.
Key Terms: riparian, buffer, woody debris, cumulative
watershed effects, logging
Rice, R.M. 1987. Cumulative impacts: current research and
current opinions at PSW. In: Proc. Impact '87, Annual Convention
of California Licensed Foresters Association; 1987 March 6-7,
1987; Pioneer, CA; 1-12.
In 1985, scientists at the USDA Forest Service, Pacific Southwest
Forest and Range Experiment Station (PSW) began collecting data in
the Caspar Creek watershed for a study specifically designed to
address cumulative watershed effects (CWEs).
Key Terms: cumulative watershed effects, sedimentation, logging, roads
Rice, R.M. 1991. Cumulative watershed effects: can they be
measured? What have we learned from the Caspar Creek studies in
northern California? In: The 1990schallenging our profession
and professionalism. Summaries of the proceedings of the 1990
western forestry conference, 1990 December 2-5; Coeur d'Alene, ID.
Portland, OR: Western Forestry and Conservation Association; 92.
Cumulative Watershed Effects (CWEs) may be additive or
synergistic. Additive CWEs are the sediment accumulation downstream caused
by various activities (such as road construction). Synergistic effects
are aggregates of additive CWEs. Even though Best Management
Practices (BMP) are applied, synergistic CWEs may result in an
unacceptable amount of suspended sediment in a stream and trigger
additional impacts. Current research at Caspar Creek is aimed at estimating
the magnitude of synergistic CWEs.
Key Terms: cumulative watershed effects, sedimentation, logging, roads
Rice, R.M. 1996. Sediment delivery in the North Fork of
Caspar Creek. Unpubl. Final Rept. prepared for the Calif. Dept. of
Forestry and Fire Protection, Agreement No. 8CA94077. 11 p.
Sediment delivery was estimated for 13 tributary watersheds and
the North Fork of Caspar Creek. The median ratio of sediment to
erosion was 6.3 percent. Data analyses suggest that more research is
needed for estimating sheet erosion and stream channels as sediment
sources. Compared to an earlier study in the South Fork of Caspar
Creek, logging of the North Fork resulted in erosion that was about half
as large and a sediment delivery ratio that was also about half of the
1979 estimate.
Key Terms: sedimentation, erosion, logging, roads
Rice, Raymond M. 1998. Where do we go from
here? In: Ziemer, Robert R., technical coordinator. Proceedings of the conference
on coastal watersheds: the Caspar Creek story, 1998 May 6; Ukiah,
CA. Gen. Tech. Rep. PSW-GTR-168. Albany, CA: Pacific
Southwest Research Station, Forest Service, U.S. Department of
Agriculture; 135-136.
Suggests that future research in the North and South forks of
Caspar Creek is to make of them a continuing study of the two main
opposing silvicultural systems: even- and uneven-aged management. The
South Fork has had one partial cut more than 25 years ago and is ready
for another. The North Fork already has no adjacency problems;
therefore, additional clearcuts could be made at any time. Hopefully,
these analyses would include biological concerns as well as
hydrologic effects.
Key Terms: paired watersheds, future study, monitoring,
land management, resource issues
Rice, Raymond M. 1998. Why Caspar Creekthen and
now? In: Ziemer, Robert R., technical coordinator. Proceedings of
the conference on coastal watersheds: the Caspar Creek story,
1998 May 6; Ukiah, CA. Gen. Tech. Rep. PSW-GTR-168. Albany,
CA: Pacific Southwest Research Station, Forest Service, U.S.
Department of Agriculture; 11-13.
The results of every watershed experiment are a unique
combination of the site, the weather, the questions asked, the quality of the
data produced, and the quality of the analysis made of those data.
These results narrow the scope of the environmental debate, but they will
not alter the value systems of the debaters. By availing themselves of
the available scientific information both sides can make their cases
more persuasive to the courts, to the regulators, and
perhaps to the public.
Key Terms: paired watersheds, research
Rice, R.M.; Tilley, F.B.; Datzman, P.A. 1979.
A watershed's response to logging and roads: South Fork of Caspar Creek, California,
1967-1976. Res. Paper PSW-146. Berkeley, CA: Pacific Southwest
Forest and Range Experiment Station, Forest Service, U.S. Department
of Agriculture; 12 p.
A paired-watershed study in the North and South Forks of
Caspar Creek demonstrates the effects of logging and road building
on streamflow and sedimentation. On-site erosion, annual
suspended sediment loads, and debris basin accumulations were estimated
in order to evaluate the effects of road construction and the
timber harvest. The South Fork watershed produced a threefold increase
over that which would have been expected had the watershed
remained undisturbed. Analysis of the sediment/stream power relationship
of Caspar Creek strongly suggests that the increase in sedimentation
is due to the additional availability of logging and road-related
sediment for transport.
Key Terms: roads, logging, erosion, sedimentation
Rodriguez, Albert; Jones, Weldon. 1993. Investigations of
salmon and steelhead trout: downstream migrations in Caspar Creek
and Little River, Mendocino County, March-July,
1993. Unpublished Rept. Calif. Dept. of Fish and Game, Sacramento, CA, 14 p.
Two coastal streams were compared in order to observe the
different trend patterns of juvenile out-migrations for Coho salmon
and steelhead trout. The size, timing, growth rate, and age
classifications of salmonids were determined. Analysis of the 1993 trapping
season indicates, at Little River, a decrease of steelhead trout yearlings but
an increase in Coho yearlings. At Caspar Creek, Coho and trout
yearlings were similar in magnitude and simultaneously tapered in late May.
Key Terms: fisheries, stream ecology
Sendek, Karen Hardison. 1985. Effects of timber harvesting on
the lag time of Caspar Creek watershed. Arcata, CA: Humboldt
State University; 46 p. M.S. thesis.
Hydrograph lag time was analyzed to determine changes after
road construction and after selective, tractor-yarded logging in the
Caspar Creek watershed. Six hydrologic variables were examined as
predictors of the effect of logging on lag time. Proportion of area logged and
the ratio of proportion of area logged divided by the storm
sequence number were the best predictors. Other variables examined
were North Fork peak flow, storm sequence number, storm size,
and antecedent precipitation.
Key Terms: storm runoff, peak flow, logging, roads
Spittler, T.E. 1995. Pilot monitoring program: geologic input
for the hillslope component (includes a discussion of Caspar
Creek geology and geomorphology). Unpublished report prepared for
the Calif. Dept. of Forestry and Fire Protection, Contract
No. 8CA38400, Sacramento, CA. 18 p.
The development of hillslope monitoring techniques needed
to evaluate the effectiveness of the Forest Practice Rules in
protecting water quality is explained. The major component of Division of
Mines and Geology (DMG) work involved defining the
physical characteristics of the pilot watersheds, among them the North
and South Forks of Caspar Creek above their weir dams. DMG
also participated in the Monitoring Study Group to aid in
developing analysis techniques for evaluating hillslope processes as well
as procedures for selecting and evaluating monitoring locations for
a possible long-term monitoring program.
Key Terms: hillslope processes, geology, stream ecology, logging
Spittler, T.E.; McKittrick, M.A.. 1995. Geologic and
geomorphic features related to landsliding, North and South Forks of
Caspar Creek, Mendocino County, California. Open File Rept. OFR
95-08, scale 1:12,000. Available from: Calif. Dept. of
Conservation, Division of Mines and Geology, 801 K Street, MS
14-34, Sacramento, CA 95814-3532.
This set of two maps provides information about geology
and geomorphic features of the watersheds of North and South
Fork, Caspar Creek. The mapping for these areas was done at a scale
of 1:12,000.
Key Terms: geology, geomorphic process, landslides, mapping
Surfleet, Christopher G.; Ziemer, Robert R. 1996.
Effects of forest harvesting on large organic debris in coastal
streams. In: LeBlanc, John, ed. Conference on coast redwood forest ecology
and management; 1996 June 18-20; Arcata, CA. Berkeley, CA:
University of California; 134-136.
Large organic debris (LOD) was inventoried in two coastal
streams (the North and South Forks of Caspar Creek) to assess the impacts
of forest harvesting on LOD recruitment in 90-year-old
second-growth redwood and fir stands. LOD levels increased after harvest
because residual trees were left adjacent to the stream or in streamside
buffer strips. Windthrow of fir provided the largest input of LOD in
these stands owing to the stand age and structure of the residual
trees adjacent to the stream.
Key Terms: large woody debris, logging, buffer strips, channel morphology
Thomas, R.B. 1985. "Artificial intelligence" at streamgaging
stations. EOS, Transactions, American Geophysical Union 66(46): 912.
Stream measurement involves technical/logistical problems
of collecting and transferring data and questions of
time-related sampling. Field microprocessors using sampling algorithms and
real-time sensing of stream variables can substantially improve the
quality of stream data collection.
Key Terms: streamflow, instrumentation, sampling
Thomas, Robert B. 1985. Estimating total suspended sediment
yield with probability sampling. Water Resources Research 21(9):
1381-1388.
The "Selection At List Time" (SALT) scheme controls sampling
of concentration for estimating total suspended sediment yield.
The probability of taking a sample is proportional to its
estimated contribution to total suspended sediment discharge. When applied
to real data with known yield, the SALT method underestimated
total suspended sediment yield by less than 1 percent, whereas the
flow duration sediment rating curve method underestimated
total suspended sediment yield by 51 percent.
Key Terms: suspended sediment, instrumentation, sampling
Thomas, R.B. 1985. Measuring suspended sediment in
small mountain streams. Gen. Tech. Rep. PSW-83. Berkeley, CA:
Pacific Southwest Forest and Range Experiment Station, Forest
Service, U.S. Department of Agriculture; 9 p.
This report describes the problems in measuring suspended
sediment in small mountain streams. The factors that govern the quality of
data collected in a monitoring program are discussed.
Key Terms: suspended sediment, instrumentation, sampling
Thomas, R.B. 1988. Measuring sediment yields of storms
using PSALT. In: Bordas, M.P.; Walling, D.E., eds. Sediment
budgets, proceedings of the Porto Alegre Symposium; 1988 December
11-15; Brazil. International Association of Hydrological
Sciences Publication No. 174. Wallingford, UK: IAHS; 101-109.
To sample and estimate sediment yields in Caspar Creek,
PSALT (Piecewise Selection At List Time) a probability-based method
for sampling that enhances data collection during high flows has
been used. Because PSALT data are independent they can be combined
to give unbiased estimates of suspended sediment yield and its
variance during storms. Problems of applying the method to a large number
of basins are discussed along with their solutions.
Key Terms: suspended sediment, sampling, storm runoff
Thomas, R.B. 1989. Piecewise SALT sampling for
estimating suspended sediment yields. Gen. Tech. Rep. PSW-83. Berkeley,
CA: Pacific Southwest Forest and Range Experiment Station,
Forest Service, U.S. Department of Agriculture; 11 p.
SALT (Selection At List Time) is a method for collecting data
on suspended sediment concentration and estimating total
suspended sediment yield. The SALT estimates can consist of composites
or portions of several SALT-monitored periods, known as
"piecewise SALT sampling." This paper describes how to collect data and
estimate sediment yield and its variance by piecewise SALT sampling,
and discusses another method for setting sample size which is
particularly appropriate for piecewise SALT sampling.
Key Terms: suspended sediment, sampling
Thomas, R.B. 1990. Problems in determining the return of
a watershed to pretreatment conditions: techniques applied to
a study at Caspar Creek, California. Water Resources Research
26(9): 2079-2087.
Using a previously treated basin as a control in subsequent
paired-watershed studies requires the control to be stable. Recovering
from logging and road building in the early 1970's, the South Fork of
Caspar Creek was assessed for basin stability. The results of studying
three storm-based discharge characteristics (peak discharge, quick flow,
and total storm flow), daily flows, and concentration of
suspended sediment indicate that the South Fork has returned to
near pretreatment conditions.
Key Terms: storm runoff, suspended sediment, sampling
Thomas, Robert B.; Lewis, Jack. 1993. A comparison of selection
at list time and time-stratified sampling for estimating
suspended sediment loads. Water Resources Research 29(4): 1247-1256.
Time-stratified sampling of sediment for estimating suspended load
is introduced and compared to selection at list time (SALT)
sampling. The two methods are compared using five storm populations
of suspended sediment flux derived from turbidity data. Both
methods provide unbiased estimates of load and variance but vary in
efficiency according to storm size and duration.
Key Terms: suspended sediment, sampling
Thomas, Robert B.; Lewis, Jack. 1993. A new model for
bedload sampler calibration to replace the probabilitymatching
method. Water Resources Research 29(3): 583597.
In 1977, extensive data were collected to calibrate six
Helley-Smith bedload samplers with four sediment particle sizes in a flume at the
St. Anthony Falls Hydraulic Laboratory at the University of Minnesota.
A new calibration model was developed that regresses
transformed individual sampler measurements on daily means of transformed
trap data and incorporates within-day variation in trap rates to
explain part of the sampler variation. Results of this study can be used
to design a more rigorous calibration experiment.
Key Terms: bedload, sampling, modeling, sedimentation
Thomas, R.B.; Lewis, Jack. 1995. An evaluation of
flow-stratified sampling for estimating suspended sediment
loads. Journal of Hydrology 170: 27-45.
Flow-stratified sampling is a new method for sampling water
quality constituents such as suspended sediment to estimate loads. It is
a statistical method requiring random sampling and yielding
unbiased estimates of load and variance. Flow-stratified sampling is
described and its variance compared with those of selection-at-list-time
(SALT) and time-stratified sampling.
Key Terms: sampling, suspended sediment, storm runoff
Tilley, F.B.; Rice, R.M. 1977. Caspar Creek watershed
studya current status report. State Forest Notes No. 66. Sacramento,
CA: State of Calif., Department of Forestry; 15 p.
The primary objectives of the project are to measure the
sediment produced by a north coastal watershed in an undisturbed
condition and to measure the degree to which water quality, flood
peaks, suspended sediment, and bedload are affected by road
construction and logging when practices are designed to minimize excessive
runoff and erosion. The most apparent effects of logging the South Fork
were the increased amounts of suspended sediment and the
greater responsiveness to precipitation.
Key Terms: peak flow, suspended sediment, bedload, roads, logging
Walton, K. 1988. Downstream migrant trapping on Caspar
Creek and Little River, March-June 1988. Calif. Dept. of Fish and
Game Unpublished Rept. Sacramento, CA. 8 p.
This study was conducted to observe the different trend patterns
of juvenile out migrations for Coho salmon and steelhead-trout. The
size, timing, growth rate and age classifications of salmonids for 1988
are reported.
Key Terms: fisheries, stream ecology
Wosika, Edward Pearson. 1981. Hydrologic properties of one
major and two minor soil series of the Coast Ranges of northern
California. Arcata, CA: Humboldt State University; 150 p. M.S. thesis.
The following properties of the Hugo, Mendocino, and Caspar soil
series were analyzed at various depths: bulk density, porosity, particle
density, saturated and unsaturated hydraulic conductivity,
particle-size distribution, pore-size distribution, and water retention
characteristics. The main factor producing differences between these three series
and within the Hugo series is the degree of colluvial mixing, which is
closely related to slope position. Also, the unsaturated hydraulic conductivity
of the three series are sufficiently high at all soil depths to preclude
the large-scale development of saturated subsurface flow.
Key Terms: soils, geology, subsurface flow
Wright, Kenneth A. 1985. Changes in storm hydrographs
after roadbuilding and selective logging on a coastal watershed
in northern California. Arcata, CA: Humboldt State University; 55
p. M.S. thesis.
The effects of road building and selective tractor harvesting on
storm peak flows and storm volumes were assessed for the Caspar
Creek watershed. Only the very small storm peaks or volumes were
increased after roadbuilding and logging. The increases in small storm
peaks and volumes are not considered significant to the stream's stability
or sediment regime.
Key Terms: peak flows, storm runoff, logging, roads
Wright, Kenneth A.; Sendek, Karen H.; Rice, Raymond M.;
Thomas, Robert B. 1990. Logging effects on streamflow: storm runoff
at Caspar Creek in northwestern California. Water Resources
Research 26(7): 1657-1667.
The effects of road building and selective tractor harvesting on
storm runoff were assessed at Caspar Creek. Findings suggest no
significant increases in storm volumes and peaks of large storms by either
roads or logging. In a rain-dominated hydrologic environment, logging
and forest road construction (as carried out in this study) are not likely
to change the flow regime of a stream adversely.
Key Terms: peak flows, logging, storm runoff
Ziemer, Robert R. 1968. Fifth progress report, 1967,
cooperative watershed management research, flood and sediment reduction
in the lower conifer zone of California. Berkeley, CA: Pacific
Southwest Forest and Range Experiment Station, Forest Service,
U.S. Department of Agriculture; 9 p.
Describes work on the Caspar Creek study during 1967.
Key Terms: experimental watersheds
Ziemer, Robert R. 198l. Stormflow response to roadbuilding
and partial cutting in small streams of northern
California. Water Resources Research 17(4): 907-917.
To assess the influence of roadbuilding and logging on storm
flow response, the North Fork and South Fork of Caspar Creek were
studied from 1963 to 1975. Selection cutting and tractor yarding of
85-year-old second-growth redwood and Douglas-fir forest did not
significantly affect large peak flows. The effect of logging on peak flow was
best predicted by a variable that represented the percentage of the
area logged divided by the sequential storm number within the year.
Key Terms: streamflow, roads, logging
Ziemer, R.R. 1990. The Caspar Creek Watershedsa case
study. In: Callaham, R.Z., ed. Case studies and catalog of
watershed projects in western provinces and states. Report 22.
Davis: University of California Wildland Resources Center ; 17-19, 81.
A synopsis of the Caspar Creek Experimental Watersheds, from
their inception in 1962 to their status in 1990. The history,
problems, objectives, and planning of the study are discussed.
Key Terms: streamflow, suspended sediment, bedload,
cumulative watershed effects, logging, roads
Ziemer, R.R. 1992. Effect of logging on subsurface pipeflow
and erosion: coastal northern California, USA. In: Walling, D.E.;
Davies, T.R.; Hasholt, B., eds. Erosion, debris flows and environment
in mountain regions, Proceedings of the Chendu symposium;
1992 July 5-9; Chendu, China. International Association of
Hydrological Sciences Publication No. 209. Wallingford, UK: IAHS; 187-197.
Three zero-order swales, each with a contributing drainage area
of about 1 ha, were instrumented to measure pipeflows within the
Caspar Creek Experimental Watershed. After two winters of data
collection, the second-growth forest on two of the swales was clearcut
logged while the third swale remained an uncut control. After logging,
peak pipeflow and suspended sediment load increased.
Key Terms: subsurface flow, pipeflow, suspended sediment, logging
Ziemer, R. 1996. Caspar Creek streamflow and sediment
records: 1963-1995. CD-ROM, 200 MB. 1996 July. Arcata, CA:
Pacific Southwest Research Station, USDA Forest Service, and Fort
Bragg, CA: California Department of Forestry and Fire Protection.
This CD-ROM contains data records for the North and South Forks
of Caspar Creek from 1963-1995, including annual
precipitation, streamflow and sediment records, daily and 10-minute
streamflow records, and a compilation of all suspended sediment samples collected.
Key Terms: streamflow, suspended sediment,
precipitation, temperature, logging
Ziemer, R. 1998. Caspar Creek hydrologic and climatic data:
1963-1997. CD-ROM, 545 MB. 1998 May. Arcata, CA: Pacific
Southwest Research Station, USDA Forest Service, and Fort Bragg,
CA: California Department of Forestry and Fire Protection.
Detailed data files on this expanded CD-ROM include
streamflow (1963-1997), suspended sediment (1963-1997), rainfall
(1963-1997), solar radiation (1988-1997), channel cross-sections (1987-1997),
and air and water temperatures (1989-1997). In addition,
detailed streamflow and sediment data are included for 13 tributary
stations that were installed in the North Fork in August 1985.
Key Terms: streamflow, suspended sediment, precipitation,
solar radiation, channel morphology
Ziemer, Robert R. 1998. Flooding and
stormflows. In: Ziemer, Robert R., technical coordinator. Proceedings of the conference
on coastal watersheds: the Caspar Creek story, 1998 May 6; Ukiah,
CA. Gen. Tech. Rep. PSW-GTR-168. Albany, CA: Pacific
Southwest Research Station, Forest Service, U.S. Department of
Agriculture; 15-24.
The effects of road building and timber harvest on storm flow
were evaluated by studying 174 storms from 1963 through 1975
that produced peak discharges in the untreated North Fork larger
than 0.016 L s-1ha-1. These smallest storm peaks occur on average about
14 times each year. Flows this size and larger occupy about 10 percent
of the time, are responsible for 83 percent of the annual water
discharge, and transport 99 percent of the suspended sediment. In 1985,
an additional 13 gaging stations were installed in the North Fork.
From 1985 through 1996, 526 peakflow observations were
made, representing 59 storms. There was a mean peakflow increase of
35 percent in entirely clearcut and 16 percent in partially
clearcut watersheds for the class of flows greater than 4 L
s-1ha-1.
Key Terms: paired watersheds, peak streamflow
Ziemer, Robert R. 1998. Monitoring watersheds and
streams. In: Ziemer, Robert R., technical coordinator. Proceedings of
the conference on coastal watersheds: the Caspar Creek story,
1998 May 6; Ukiah, CA. Gen. Tech. Rep. PSW-GTR-168. Albany,
CA: Pacific Southwest Research Station, Forest Service, U.S.
Department of Agriculture; 129-134.
Regulations increasingly require monitoring to detect
changes caused by land management activities. Successful
monitoring requires that objectives be clearly stated. Once objectives are
clearly identified, it is important to map out all of the components and
links that might affect the issues of concern. Each issue and
each component that affects that issue has a set of spatial and
temporal scales within which they operate. These scales are not
consistent between and amongst one another. For many issues, unusual
events are more important than average conditions. Regulations
developed from the consequences of small "normal" storms will be
inadequate in that the data will not include the critical geomorphic events
that affect the physical and biological concerns.
Key Terms: paired watersheds, peak streamflow, monitoring,
land management, resource issues
Ziemer, Robert R. 1998. Preface. In: Ziemer, Robert R.,
technical coordinator. Proceedings of the conference on coastal
watersheds: the Caspar Creek story, 1998 May 6; Ukiah, CA. Gen. Tech.
Rep. PSW-GTR-168. Albany, CA: Pacific Southwest Research
Station, Forest Service, U.S. Department of Agriculture; iii-iv.
The Conference was held May 6, 1998 at the Mendocino
Community College in Ukiah, California, and was attended by about 400
persons. On May 7, 75 individuals participated in a field trip through the
North Fork of Caspar Creek. There is keen interest in the effect of
forest practices on the hydrologic response of watersheds. Attendance
at both the Conference and the field trip was limited by seating
capacity and a large number of potential registrants were turned away
because of lack of space.
Key Terms: paired watersheds, conference, coastal watersheds
Ziemer, Robert R., technical coordinator. 1998.
Proceedings of the conference on coastal watersheds: the Caspar Creek
story. 1998 May 6; Ukiah, CA. Gen. Tech. Rep. PSW-GTR-168. Albany,
CA: Pacific Southwest Research Station, Forest Service, U.S.
Department of Agriculture;
149 p.
Proceedings contain a preface, 15 papers, and a detailed
annotated bibliography of papers produced during 36 years of research in
the Caspar Creek Experimental Watershed.
Key Terms: paired watersheds, streamflow, sediment,
nutrient, riparian, cumulative effects, soil moisture
Ziemer, R.R.; Albright, J.S. 1987. Subsurface pipeflow dynamics
of north-coastal California swale systems. In: Beschta, R.; Blinn,
T.; Grant, G.E.; Swanson, F.J.; Ice, G.G., eds. Erosion
and sedimentation in the Pacific Rim, Proceedings of the
Corvallis Symposium, 1987 August. International Association
of Hydrological Sciences Publication No. 165. Wallingford, UK:
IAHS; 71-80.
Pipeflow dynamics at Caspar Creek is discussed. During
storms, pipeflow up to 8 L s-1 has been measured, whereas, within the
same swales, no surface channel flow occurred. Pipeflow discharge has
been correlated with antecedent precipitation.
Key Terms: pipeflow, storm runoff, subsurface flow,
hillslope hydrology
Ziemer, R.R.; Cafferata, P.H. 1992. The Caspar Creek watersheds:
a case study of cumulative effects in a small coastal basin in
northern California. In: Proceedings 1991 SAF National Convention;
1991 August 4-7; San Francisco, CA. San Francisco, CA: Society
of American Foresters; 2 p.
This paper gives an overview of the Caspar Creek
experimental watersheds from 1962 to 1992. In 1985 the study was modified
to evaluate the cumulative watershed effects of logging the North
Fork. Intensively measured were precipitation, soil moisture,
groundwater, subsurface pipeflow, streamflow and suspended sediment discharge
at 15 gauging stations, bedload movement, steam channel stability,
large woody debris, and anadromous fish habitat.
Key Terms: cumulative watershed effects, streamflow, storm
runoff, sedimentation, logging, roads
Ziemer, Robert R.; Kojan, Eugene; Thomas, Robert B. 1965.
Third progress report, 1965, cooperative watershed management in
the lower conifer zone of California. Berkeley, CA: Pacific
Southwest Forest and Range Experiment Station, Forest Service,
U.S. Department of Agriculture; 33 pp.
Describes instrumentation and presents data on streamflow,
precipitation, and sedimentation collected between October 1, 1963 and September
30, 1965. Discuses the stream ecology study conducted by John
DeWitt, Richard Ridenhour, and James Andrews of Humboldt State College.
Key Terms: experimental watersheds, stream ecology
Ziemer, Robert R.; Kojan, Eugene; Thomas, Robert B.;
Muller, Robert A. 1966. Fourth progress report, 1966,
cooperative watershed management research, flood and sediment reduction
in the lower conifer zone of California. Berkeley, CA: Pacific
Southwest Forest and Range Experiment Station, Forest Service,
U.S. Departmetimesnt of Agriculture; 88 p.
Describes instrumentation and presents data on
streamflow, precipitation, and sedimentation collected between October 1,
1963 and September 30, 1965. Discuses the stream ecology study
conducted by John DeWitt, Richard Ridenhour, and James Andrews of
Humboldt State College.
Key Terms: experimental watersheds, stream ecology
Ziemer, Robert R.; Lewis, Jack; Keppeler, Elizabeth T.
1996. Hydrologic consequences of logging second-growth
watersheds. In: LeBlanc, John, ed. Conference on coast redwood forest ecology
and management; 1996 June 18-20; Arcata, CA. Berkeley, CA:
University of California; 131-133.
Streamflow, suspended sediment, and bedload have been
gauged continuously since 1962 in the 473-ha North Fork and the
424-ha South Fork of Caspar Creek. During the course of the study,
logging roads were built and approximately 65 percent of the timber
volume was selectively cut in the South Fork and clearcut in the North
Fork. Large peak flows did not change significantly in either watershed.
To date, the effect on sediment loads of logging in the North Fork
has been much smaller than that following logging in the South Fork.
Key Terms: streamflow, peak flow, suspended sediment,
bedload, logging
Ziemer, R.R.; Rice, R.M. 1990. Tracking rainfall impulses
through progressively larger drainage basins in steep forested
terrain. In: Lang, H.; Musy, A., eds. Hydrology in mountainous regions. I
- Hydrological measurements; the water cycle, proceedings of
two Lausanne symposia, 1990 August. International Association
of Hydrological Sciences Publication No. 193. Wallingford, UK:
IAHS; 413-420.
The precision of timing devices in modern electronic data
loggers makes it possible to study the routing of water through small
drainage basins having rapid responses to hydrologic impulses. By using
such means as digital tipping bucket raingauges, naturally occurring
soil pipes, streamflow gauging stations, and piezometers, stream
discharge and routing can be measured. Peak lag time increased
significantly downstream, and peak unit area discharge decreased downstream.
Key Terms: precipitation, storm runoff, subsurface flow
|
|
|
|
