More comprehensive analysis of Klamath River basin needed to aid decision makers

Two recent scientific studies attempt to better understand the Klamath River basin ecosystem. However, a new report from the National Research Council says for the studies to prove more useful for decision makers, a comprehensive analysis of the basin should be completed to identify all research and management needs. The studies included models that were intended to help reconstruct pre-development flows — without dams or irrigation — and to help understand the relationship between flows in the Klamath River and the amount of river habitat available for use by anadromous fishes, which start life in freshwater, migrate to the ocean to grow and mature, and return to freshwater to spawn.

“Science is being done in bits and pieces, and there is no conceptual model that gives a big picture perspective of the entire Klamath River basin and its many components,” said William L. Graf, professor of geography at the University of South Carolina, Columbia, and chair of the committee that wrote the report. “As a result, the integration of individual studies — such as the two examined by the committee — into a coherent whole has not taken place, and it is unlikely to take place under the present scientific and political arrangements.”

The Instream Flow Phase II study (IFS), conducted by Utah State University, modeled and assessed flows in the Klamath River and their relationship to the amount of useable habitat that would be available to coho salmon and other anadromous fishes in the main stem of the Klamath River, downstream from Iron Gate Dam. The Natural Flow of the Upper Klamath Basin study (NFS), conducted by the U.S. Bureau of Reclamation (USBR), estimated flows that would occur if there were no agricultural development or diversion of flows, such as by dams and irrigation, in the upper Klamath River basin. The flow estimates from NFS also served as inputs for IFS. The U.S. Department of the Interior asked the Research Council to review and evaluate the methods and approaches used in the IFS and the NFS and to assess the implications of the studies' conclusions for the basin's anadromous fishes, as well as to identify additional information needed to enhance understanding of the basin ecosystem.

In its review, the committee found that the IFS uses many innovative and cutting-edge methods in modeling the relationship between flows in the Klamath River and the amount of available fish habitat. The committee concluded that the IFS recommendation for increased flows downstream from Iron Gate Dam probably would benefit the river's anadromous fishes in general — although not necessarily any one species — by increasing the availability of habitat. The IFS prescribed flow rates would not likely have adverse effects on any of the anadromous fish species, the committee judged.

Despite its strengths, the IFS has several inadequacies — especially in its use of monthly instead of daily data and its lack of tributary analyses — which are so severe that they would need to be addressed before decision makers could use the outputs of the study to establish precise flow regimes with confidence, the committee noted. For instance, monthly flow values could mask the effects of flow rates that last only a few days or less, but adverse conditions in that short amount of time could prove detrimental to fish populations. Although the IFS authors recognized that daily flows were more useful, the USBR provided only the monthly flow estimates developed in the NFS.

Furthermore, analyzing the river without considering its tributaries — which provide essential characteristics and some of the most important habitats in the basin — is akin to analyzing a tree by assessing only its trunk, but not its branches, the committee stated. The omission of tributary processes apparently resulted from an agreement reached by basin managers to simplify the engagement of stakeholders in the process.

The careful documentation and analysis of the NFS provides a foundation for future studies, gives some basis for understanding unimpaired flows in the basin, and allows a clearer vision of how the parts of the Klamath River basin — especially areas above Upper Klamath Lake — interact with each other, the committee said. However, the NFS includes calculated flows that are at best first approximations to useful estimates of flows, and it does not provide enough information for detailed management of flows for the benefit of threatened, endangered, and other anadromous fish species in the Klamath River downstream from Iron Gate Dam.

The most critical shortcomings of the NFS are its inadequate linkages between the Klamath River and Lower Klamath Lake, and the study's production of monthly, rather than daily flows. Additionally, the NFS is compromised by its basic approach to natural flows, choices of the models for calculations, and omissions of factors likely to influence river flows at the Iron Gate Dam gauge site. For example, the NFS does not factor in the role of groundwater, which should be included because groundwater pumping and marsh drainage are common to help meet agriculture needs. Also, the model results indicate that if more water is devoted to agriculture, more water would be returned to the Klamath River. The committee stressed that although such a result is not impossible, it is at least counterintuitive and should be explored and explained completely.

To move forward on science and management in the basin, the committee recommended that key agencies, researchers, decision makers, and stakeholders work together with an independent science review mechanism to define a basin-wide science plan that identifies research and management needs and priorities. If this group determines that the NFS and the IFS could help satisfy science needs in the basin, investigators should improve both studies by using daily flows as a basis for their calculations and by addressing the shortcomings in the studies identified by the committee.