Slide 1

Outline

• Kittitas Reach study for YRBWEP (Schaake Project)
• Water storage study for habitat inventory and geomorphology
• Advancements in bathymetric surveys
• Future studies related to gravel pits
• Sediment modeling with SIAM
• Conclusions

Schaake Project

• Purpose – to improve habitat conditions and address potential flooding issues
  • Two reports to YRBWEP
  • Interim report detailing a geomorphic study
    • Included a historic and geomorphic study of previous channel forms and locations using 1912 survey and 1966 aerial photography
    • Determined the level of channel incision and anticipated frequency of floodplain inundation using a 1-D hydraulic model and 27 years of gage data
  • Final report detailing proposed levee setback and pilot channel locations
    • Three levee scenarios modeled in two dimensions to evaluate flooding
    • Smaller scale 2-D model to study interaction between pilot channels and main channel

Schaake Project

Schaake Project

Schaake Project

Schaake Project

Schaake Project

Schaake Project

Schaake Project

Schaake Project

Water Supply Project

• Need to provide input for Ecosystems Diagnostic and Treatment (EDT)
• Hydraulic Modeling (1-D and 2-D)
  • 1-D hydraulic model (Upper Columbia Area Office) for coarse evaluation of hydraulic conditions (wetted width, cross section velocities, etc.)
  • 2-D hydraulic model determines habitat quantity and quality on a finer scale for a few selected reaches (4 – 12 miles)
• Determine sediment transport conditions using SIAM
  • Provide input to EDT
  • Gain an understanding of potential channel change following increased flow

2-D Hydraulic Modeling

• Model used is GSTAR-W (Generalized Sediment Transport for Alluvial Rivers and Watersheds), a comprehensive watershed model incorporating overland flow, channel flow and sediment transport (being developed in-house)
  • OVERLAND FLOW
    • Rainfall runoff, interception, evaporation and transpiration, infiltration, and saturated zone/channel interaction
  • CHANNEL FLOW - 1-D and 2-D solutions
    • 2-D solutions offer dynamic or diffusive wave, implicit or explicit solutions
  • SEDIMENT TRANSPORT
    • Overland and channel transport and deposition
    • Can assess TMDLs

2-D Model

• The current application uses the channel network portion of GSTAR-W
  • Finite element, diffusive wave, implicit solution for depth averaged velocity and water depth
• Deliverable products
  • Depth and velocity at various steady state flows
    • Shape files compatible with Arc GIS

2-D Hydraulic Model

• Mesh generation
  • Combined structured/unstructured curvilinear mesh
    • Structured portion represents the main channel
    • Unstructured portion represents the overbank areas
  • The combination of a structured and unstructured mesh optimizes model development, computation time, and representation of channel form and hydraulics

Preliminary Results, 2-D Model

Preliminary Results, 2-D Model

Preliminary Results, 2-D Model

Preliminary Results, 2-D Model

Preliminary Results, 2-D Model

Bathymetric LiDAR

• SHOALS-1000T bathymeter manufactured by Optech
• Previous to flights on the Yakima River in Sept. 2004, this survey method was limited to coastal applications
• Kittitas and Easton reaches were flown in Sept. 2004
• Five other reaches of the Yakima and Naches rivers flown in Apr/May 2005
• Requires mostly clear water for successful data collection

Bathymetric LiDAR

Bathymetric LiDAR

Bathymetric LiDAR

Bathymetric LiDAR

• Advantages of aerial method
  • Boating/rafting safety not an issue
  • No access issues
  • Much faster data collection (~ 13 river miles/day)
  • No post processing by Reclamation
  • Little or no ground support required by Reclamation
  • Data delivered within 60 days
  • Much denser coverage (2x2 m spot spacing)
  • Data can be collected in side channels not accessible by boat or raft

Slide 26

Slide 27

Bathymetric LiDAR

Bathymetric LiDAR

Bathymetric LiDAR

• Example of areas with spotty coverage

Bathymetric LiDAR

Bathymetric LiDAR

• Statistical comparison with ground truth data for accuracy and precision

Gravel Pits

• Dave Norman et al. (WaDNR) have documented the hazards of pit capture of floodplain mines by the Yakima and other rivers
  • Washington Geology, September, 1998
• Also documented are the potential benefits of incorporating these pits into the normal flow of the river
• Floodplain Mining Impact Study recommends a study for reclaiming floodplain mines
• Several floodplain pits have already avulsed, including:
  • Gladmar, I-90, Selah, Parker and others

Gravel Pits

• Discussions are on-going with Yakima County to begin a multi-agency effort to study the feasibility of connecting the floodplain mines to the main flow of the river
  • Levee set-back
  • Partial fill of pits with old levee material
  • Force partial river flow into and out of gravel pit(s)
  • Partial sediment load in river to fill remaining volume over time
  • This effort will create a multi-channel system
    • In some reaches of the Yakima River, this is a natural configuration

Gravel Pits

Gravel Pits

• Meeting in July is tentatively planned
  • Meet with potential partners
  • Present initial study plan
  • Take input from partner organizations
  • Develop a plan of study, timeline and budget

Sediment Transport – SIAM Overview

• Data Products Include: Channel Stability and Adjustment, Sediment Yield, and Sediment Supply – Impact Linkages

Key SIAM Concepts

• Rapid Assessment: SIAM provides a transparent computation model to take advantage of geomorphic principles for simulating sediment movement and channel interactions.
• Scalable Inputs: The model can range from small to very large channel networks at varying levels of detail.
• Source – Impact Linkages: SIAM identifies individual constituents contributing to a sediment impact.
• Synthesis Tool: SIAM brings together disparate and independent process models to draw conclusions on ultimate impact.
• Trend Analysis: SIAM provides the magnitude and direction of change, not ultimate conditions, adjustment time frames, or intermediate states.
• Regime Input: SIAM operates on the full range of hydrology, hydraulics, and sediment loadings through flow-duration curves.

Basic Conceptual Model

• Model Input
  • Hydrology, Hydraulics, and Sediment Transport
  • Local Sediment Sources
  • Bed Material Composition and Properties
• Bed and Wash Transport Modes
  • Immediate connection and impacts through the wash reservoir
  • Longer term morphology connection through the channel reservoirs
  • Material can transition from one reservoir to another.
• Trend Analysis
  • Predicts magnitude and direction of change
  • Final state or evolution is not represented.

Example Applications

• Changes in Land Use
  • Urbanization
  • Best Management Practices
• Rehabilitation and Restoration
  • Cumulative Restoration and Stabilization Impacts
  • Sizing and Spacing of Grade Control
• Planning and Management
  • Altered Flow Regimes
  • Identification of Causality
  • Impact mitigation

SIAM Application to Yakima Basin

• HEC-RAS Model will provide hydraulics
• Bed material sampling will specify the composition of the channel and sediment transport parameters
• Each hydrologic regime will represent a different SIAM scenario
• Data Products Include
  • Evaluate Channel Stability
  • Determine Source and Sink Reaches
  • Evaluate Fining or Coarsening of the Bed
  • Identify potential areas requiring mitigation
• The SIAM model may identify reaches which could benefit from a more detailed mobile boundary model.

Conclusions

• The TSC is available to assist Reclamation region and area offices with collaborative efforts with local, state and federal agencies as well as tribes
• Reclamation’s TSC is funded through clients willing to hire us