For the first time, a collaborative study [http://iopscience.iop.org/1748-9326/8/1/014039] has compared water quality trends in forested streams across the country that are largely undisturbed by land use or land cover changes. The study draws on 559 years of stream nitrate and 523 years of stream ammonium data from 22 streams in 7 experimental forests across the country. The study found that even near-pristine forested streams are subject to change.
The Kings River Experimental Watersheds hosts the Southern Sierra Critical Zone Observatory--a National Science Foundation effort to gain a better understanding of the zone of earth where "rock meets life." The critical zone extends from the tops of the trees to the groundwater and covers the entire earth where there is land. Download the video created by a UA Flandrau Science Center team to introduce the motivation and science involved in the National Critical Zone Observatory research program.
Kings River Experimental Watersheds (KREW)
KREW Research Overview
The Kings River Experimental Watersheds (KREW) is a watershed-level, integrated ecosystem project for headwater streams in the Sierra Nevada. Eight sub-watersheds have been chosen and fully instrumented to monitor ecosystem changes: four on the Big Creek drainage, three on the Dinkey Creek drainage, and one that drains directly into the North Fork, Kings River. Watersheds are located in two groups; the Providence Creek Site is located in mixed-conifer forest from 1500-2120 m (4920-6950 ft) elevation, and the Bull Creek Site is located in red fir/mixed-conifer from 2050-2480 m (6720-8150 ft) elevation. Each watershed will receive one of three management treatments, or serve as a control. The three treatments will be uneven-aged group selection thinning, prescribed fire, and a thinning with burn combination.
Characteristics of streams and rivers serve as integrators of broader environmental conditions because they reflect the conditions of the surrounding landscape (Hunsaker and Levine, 1995; Naiman and Bilby, 1998). Activities within a watershed, whether natural or anthropogenic, influence the most basic aspects of the hydrologic cycle. Vegetation absorbs and transpires water to the atmosphere; roads channelize water to streams; wildfire and logging decrease soil permeability; and dams alter the timing, frequency, and intensity of peak flows. All of these alterations directly impact habitat, trophic structure, and species demography, as well as physical and chemical processes.
Although stream conservation and preservation have recently become the priority of many agencies throughout North America (Naiman et al. 2000), what is considered appropriate management for forest ecosystems is a point of debate (U.S. Forest Service 2001). In contrast to terrestrial wildlife, the Forest Service in the Pacific Southwest has focused comparatively little attention and resources on forested stream ecosystems. Considering the current trends in human population growth and resource consumption, the protection and conservation of streams and rivers must become a priority for management agencies. Water quantity and quality is especially important in California's semi-arid climate. National forest land supplies approximately 60-70% of surface water.
Video: Trends in Stream Nitrogen Concentrations
The importance of roles like that played by KREW in watershed research can be demonstrated in this short video produced by the Pacific Northwest Research Station. It highlights some of the long-term research being done in other experimental watersheds and forests within the United States, using similar methods as KREW.
Current Project Status
KREW began collecting research data in 2002 for the Providence Creek locations and in 2003 for the Bull Creek locations. Data collection has continued throughout the pre-treatment phase of the project, providing nearly 9 to 10 years worth of stream discharge, water and soil chemistry, and meteorological data for the eight study watersheds. The KREW project was designed from the outset to continue for at least 15 years, including several years of post-treatment data, and several seasons of data that span successive treatments.
Kings River Experimental Watershed Forest Health and Research Project - Final Environmental Impact Statement (EIS)
The release of the final environmental impact statement (EIS) in April 2011 cleared the way for treatments to begin, the second major phase of the KREW project. The final KREW EIS documents are available here.
From July to November 2012, the first treatment phase was completed. This timber harvest and mechanical thinning activity was performed in the Providence Creek and Bull Creek areas, including four KREW research watersheds specifically selected for the mechanical thinning treatment. The prescribed fire treatment phase will commence in Fall 2013 for the Bull Creek area, followed by the Providence Creek area in Spring 2014.
|P301||Thin and Burn|
|P304||Control (no treatments)|
|B204||Thin and Burn|
|T003||Control (no treatments)|
The quality of aquatic, riparian (near-stream area), and meadow ecosystems is directly related to the integrity of adjacent uplands in their watershed. Forest Service scientists believe that these ecosystems are the most altered and impaired habitats of the Sierra Nevada primarily because of dams and diversions, overgrazing, roads, logging, and physical alteration. However, no long-term experimental watershed studies existed in the southern Sierra Nevada prior to the establishment of KREW. Work began on the Kings River Experimental Watershed (KREW) in 2000 with data collection starting in October 2002.
KREW has the following objectives:
- Quantify the variability in characteristics of stream ecosystems and their associated watersheds.
- Evaluate the effects of forest management (prescribed fire and uneven-aged, small-group tree harvesting) for forest restoration and fuels reduction.
- Maintain a mosaic of vegetation types and ages that mimic, to the extent possible, the historical distribution of vegetation resulting from frequent, low-intensity fires prevalent before European settlement of the West.
The Sierra Nevada Framework posed several management questions that KREW will address:
- What is the effect of fire and fuel reduction treatments (i.e., thinning of trees) on the riparian and stream physical, chemical, and biological conditions?
- Does the use of prescribed fire increase or decrease the rate of erosion (long term versus short term) and affect soil health and productivity?
- How adequate and effective are current stream buffers at protecting aquatic ecosystems?
KREW will also address many basic and applied questions about headwater watersheds, streams, and riparian areas. These are outlined in detail in the KREW Research Study Plan, September 2007 revision (PDF)
KREW Research Locations
KREW is located on the Sierra National Forest, High Sierra Ranger District, east of Shaver Lake, California. One of the KREW control watersheds (T003) is located on the Teakettle Experimental Forest.
More details on the KREW research locations can be found on the following pages:
KREW Project Contact
Carolyn Hunsaker - Research Ecologist, USDA Forest Service - PSW