holistic approach

Mitigating the impacts of stream and lake regulation in the Flathead River catchment, Montana, USA: an ecosystem perspective

Volume: 
Vol. 2( ) 35-36
Year: 
1992
Abstract: 

1. Seventy-two per cent of the Flathead River catchment (22,241 km^2) is federally designated and protected as wilderness or national park. Thus, the catchment remains one of the more pristine areas of its size in the temperate latitudes of the world.
2. Discharge in the downstream reaches of the river system outside the protected areas is regulated by three dams for flood control and hydropower production. These dams have blocked natural migration of native fish from Flathead Lake (496 km^2) and isolated populations in sub-catchments. Temperature and erratic flow fluctuations have altered phenologies of river zoobenthos and fish, and in dam tailwaters aquatic biodiversity is drastically reduced in comparison to unregulated segments.
3. Ecological problems caused by changing water quality conditions, altered land-use patterns and introductions of no-native biota are interactive with the impacts of stream and lake level regulation , thereby emphasizing the complexity of this river-lake ecosystem.
4. Mitigation of the effects of regulation is compromised by differing management priorities and regulatory mandates of County, State, Tribal, and Federal agencies responsible for natural resource management within the catchment. Moreover, economic and ecological interests outside the Flathead influence the way flows are regulated within the catchment.
5. The most pervasive influences of stream and lake regulation can be ameliorated by retrofitting the hypolimnial release dam with a selective depth outlet structure to allow temperature control, and by controlling changes in flow rates to create a more natural hydrograph in the tailwaters of the large dams. Allowing fish passage by construction of fish ladders is problematic because upstream passage will commingle native species that were isolated upstream by construction of the dams with non-native species that were introduced subsequently below the dams. Cascading food web interactions elicited by invasions of non-native biota may offset any advantage to native stocks gained by passage and/or augmentation with hatchery stocks.
6. Mitigation must be adaptive in the sense that unanticipated effects and interactions with other management objectives can be documented and alternative action can be implemented.
7. This case history of the effects of stream and lake level regulation, and the approaches to management reviewed in this paper, should serve as a lesson in river conservation.

Author(s): 

Stanford , J.A. , Hauer , F.R.

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Notes: 
Category: 

Exploring how disturbance is transmitted upstream: going against the flow

Volume: 
Vol. 16(2) 425-438
Year: 
1997
Abstract: 

Modifications of lower watersheds such as water abstraction, channel modification, land-use changes, nutrient enrichment, and toxic discharge can set off a cascade of events upstream that are often overlooked. This oversight is of particular concern since most rivers are altered by humans in their lower drainages and most published ecological investigations of lotic systems have focused on headwater streams. Factors contributing to ecological processes or biophysical legacies in upper watersheds often go unacknowledged because they occur at disparate geographic locations downstream (e.g., gravel mining, water abstraction, dams) with significant lag times. This paper considers examples of how alterations to streams and rivers in their lower reaches can produce biophysical legacies in upstream reaches on levels from genes to ecosystems. Examples include: 1) genetic- and species-level changes, such as reduced genetic flow and variation in isolated upstream populations; 2) populations-and community-level changes that occur when degraded downstream areas act as population "sinks" for "source" populations of native species upstream or, conversely, as "source" populations of exotic species that migrate upstream; and 3) ecosystem-and landscape-level changes (e.g., nutrient cycling, primary productivity, regional patterns of biodiversity) that can occur in headwater systems as a result of downstream habitat deterioration and hydrologic modifications. Finally, a case study from my own research illustrates the importance of careful consideration of downstream-upstream linkages in formulating research questions, designing experiments, making predictions, and interpreting results. The effects of dams and associated water abstraction in lowland streams of Puerto Rico has forced my colleagues and me to re-evaluate the results of ecological research that we have conducted in highland streams over the past decade and to redirect our research that we have conducted in highland streams over the past decade and to redirect our research to consider downstream-upstream linkages.

Author(s): 

Pringle , C.M.

Contact: 

Pringle, Catherine, Inst. Of Ecology, Univ. of Georgia, Inst. Of Ecology, University of Georgia, Athens, GA, 30602-0000

Notes: 
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Development of an Holistic Approach for Assessing Environmental Flow Requirements of Riverine Ecosystems. Water Allocation for

Volume: 
pp 69-79
Year: 
1992
Abstract: 

In this paper we describe the key features of the holistic approach for assessing the environmental flow requirements of riverine ecosystems. We identify the fundamental features of the natural hydrological regime which are of ecological importance, each of which would require an allocation of water, and then describe how these individual water allocations are used to rebuild a modified flow regime. In taking this approach, we have identified many deficiencies in our understanding of ecological responses to streamflow, and have outlined some of th emost important and demanding topics for further research. Finally, we stress the need for closer collaboration among ecologists, hydrologists, engineers and water managers in the development of water allocation strategies and environmentally sound approaches to river management.

Author(s): 

Arthington, A.H., King, J.M., O'Keffe, J.H.

Contact: 
Notes: 

American Rivers produced abstract

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