New projects

Demonstrating Innovative River Restoration Assessment Technologies: McCarran Ranch, Truckee River, Nevada

PI: Dr. Shawn Benner, Division of Hydrologic Sciences, Desert Research Institute, 775 Flamingo Rd. Las Vegas, NV 89119 USA

COE Collaborators: Dr. Stephen H. Scott, USACE ERDC-WES, CEERD-HC; Dr. Craig Fischenich, USACE ERDC-EL

Local Stakeholders: Terri Svetich, City of Reno; Jason Kuchnicki, NDEP

Problem Statement

The Nature Conservancy, with financial support from the City of Reno, City of Sparks, NDEP, U.S. Fish and Wildlife Service, and other corporate, government, and private donors, is undertaking a restoration demonstration project on five miles of the Lower Truckee River on the property of the former McCarran Ranch, located approximately 15 miles downstream from Reno, Nevada. This project reflects the emerging awareness of the benefits of linking flood control activities with restoration and improvements in environmental quality in urban watersheds of the arid and semi-arid Southwestern U.S. The success of this restoration effort is dependent on the project demonstrating measurable success on three broad, locally-defined, objectives: 1) peak flow reduction via enhanced channel-flood plain connectedness, 2) improved aquatic and riparian ecological health, and 3) increase in nutrient (nitrate and phosphate) attenuation capacity of the river/riparian system.

As a result of channelization, and other land management practices, the present-day Lower Truckee River is straighter and wider, has a steeper channel and is hydraulically disconnected from the adjacent floodplain compared with conditions that existed prior to the arrival of European settlers. The long-term objective of the river restoration project is to return the river and the riparian corridor to pre-1850 conditions. Specifically, the primary structural components of the restoration along the 5-mile McCarran Ranch Reach will be:

• The construction of eight meander lobes
• Installation of a grade control structure at the downstream end of the site with the objective of raising the channel bed a meter over the length of the reach
• Narrowing the new channel
• Construction of wetlands in the adjacent floodplain

Specific Objectives

It is hypothesized that the above-described structural changes to the McCarran Ranch river and floodplain system will dramatically alter the physical and hydraulic regime, and associated biotic communities.

The two primary objectives of this project are:

To evaluate innovative assessment technologies; the collection of characteristic datasets before and after the restoration activities provides a high degree of constraint and unique opportunity for the evaluation of predictive design and assessment tools for restoration efforts.

To demonstrate the benefits of an integrated approach to restoration assessment; because the processes are interconnected, an approach that assesses all of these processes simultaneously has two significant and practical benefits: the identification of single datasets that can meet multiple needs will greatly reduce effort and costs associated with assessment of these systems and concurrent evaluation of disparate components can elucidate otherwise poorly understood linkages, providing a level of understanding that will improve engineering approaches and increase the likelihood of future restoration designs achieving all objectives.

The field-component of this project will focus on the collection of physical parameters characteristic of restoration-induced changes. This data is of particular utility for two reasons; first it is critical to assessing the stability of the river geometry and design and, second, it can be an easily measured and highly quantifiable measure of ecological integrity. It is anticipated that changes in river channel geometry will provoke significant alteration to the velocity flow distribution and associated sediment carrying capacity of the river. Therefore, this system provides a unique opportunity to evaluate tools for assessing stream stability. Furthermore, flow velocity distribution is emerging as a key parameter controlling aquatic communities (algal, fish and macroinvertebrate). The ecological integrity of aquatic systems is governed by the collective health of algal, fish, and aquatic macroinvertebrate communities. Coordinated monitoring activities on the restoration site are targeted at the quantification of these direct measurements. However, in many cases, these chemical and biological systems are controlled by the physical flow distribution; and quantifying changes to the physical and hydraulic system can be an effective ‘biological’ assessment tool. The large and interdisciplinary nature of the datasets that will be collected for McCarran Ranch restoration provide a unique opportunity to evaluate a suite of integration techniques and assessment tools linking ecological and physical systems. A primary focus of our data analysis effort will be to integrate the ecological and physical assessment processes.

Proposed Methods

Task 1. Development of Data Collection Protocol. Because the collection of multiple-use datasets is a primary objective of this project, development of well-designed data collection protocols is critical and requires the integration of physical and biological approaches. In this task, PI’s will develop data collection protocols in close collaboration with USACE and local scientists to coordinate these efforts. The collected physical data will be integrated with parallel efforts focused on biological and chemical systems. This task will be assisted by the efforts of the DRI Data Fusion Group.

Task 2. Data Collection. Sixteen (16) river transects will be undertaken along the McCarran Ranch Reach of the Truckee River. Along these transects, data will be collected describing channel depth and geometry, sediment size and distribution, flow velocity and distribution.

Out Year Tasks. Data collected before the restoration will be used as input to numerical assessment tools (e.g. physical and hydraulic models, SAM, SIAM, 2D sediment modeling; and ecological models, HEC-EFM) to predict the conditions following restoration. A second dataset will then be collected after the restoration utilizing the methods previously developed. The model-predicted outcomes will be compared with the actual outcome to validate the modeling tools. The most accurate and/or cost-efficient approaches will then be identified. The resulting package will represent a significant resource, both for the evaluation of coupled modeling tools and for illuminating linkages for improving engineering and design. The results will be compiled into a guidance document and will be distributed utilizing both web-based and traditional information distribution mechanisms.

Anticipated Data Needs

It is anticipated that USACE-Sac. Dist. Office and/or the Washoe County Flood Control District will provide data on existing cross-sections.

Deliverables and Timeline

March 31, 2003: Description of data collection approach, dataset documents presenting physical data collected.

Out Years: Detailed assessment of relationships between hydrologic, physical, and biotic characteristics of the riparian and aquatic systems, performance evaluation of modeling tools and identification of critical datasets, provide a report of the analytical and empirical relations for dynamic equilibrium channel design, evaluation of channel design alternatives on the stabilization of the study reach.