NHC's sedimentation engineering studies are often conducted with geomorphic studies that examine erosion hazards, sediment sources, stream morphology and processes, and associated habitat problems.
Our sedimentation engineering services include:
- Numerical Modeling of Sediment Sources
Measuring and numerically modeling sediment yields from different landforms, soils, and land uses.
- Numerical Modeling of Sedimentation
Measuring and numerically modeling sediment transport modes in rivers, canals, and flood control channels, and sediment deposition in lakes, reservoirs, and estuaries.
- Erosion Control
Selecting methods, systems, and materials to prevent or reduce erosion at engineering facilities such as flood control levees, bridge and pipeline river crossings, and water intakes.
- Sediment Management
Developing methods to manage, block, or remove troublesome sediment deposits in canals, reservoirs, and other facilities.
- Field Assessments and Construction of Physical Models
These can be performed to identify sedimentation treatments to optimize pump station flow and valve operation.
Examples of NHC’s sedimentation engineering projects for public agencies and private clients include:
- Major Sediment Source Threatening Water Supply
A major water supply aqueduct was threatened by inflows of contaminated sediment delivered by a mountain stream. We conducted geomorphic, hydrologic, and sedimentation engineering studies to identify sediment sources and quantities, and alternatives for storing or bypassing sediment.
- Sedimentation of a Hydroelectric Power Canal
The water transport capacity for a hydroelectric diversion canal was severely reduced by sediment deposition during high river flows. Site investigations and analysis of remedial measures identified a solution by improving the intake works and curtailing plant diversion during brief periods of very high river flows.
- Bank Stabilization on a Large Sand River
In densely-populated agricultural Bangladesh, we conducted geomorphic and hydraulic analyses of critical riverbank segments subject to rapid erosion during floods. Our proposed bank protection, using both traditional and new erosion-protection materials, was designed and installed along with a monitoring, maintenance, and upgrading program.
- Sedimentation of a Major Hydroelectric Reservoir
We estimated reservoir sediment inflows, and modeled the two-dimensional distribution of sediment throughflows using two hydrodynamic and sedimentation software programs calibrated against measured data. Our team estimated the annual sediment accumulation patterns and sediment trap efficiencies, and characterized long-term management implications.
- Dam Effects on Downstream Channel Form
NHC used numerical modeling and other approaches to study the impact of a new dam on downstream river bed and channels. Predicted changes included substantial bed degradation immediately downstream of the dam and replacement of the braided channel by a meandering channel with greater potential for bank erosion.
Measuring sediment discharge, Sacramento River at Colusa
Sediment diversion from water intake
Stabilized meandering river
Sediment diversion at flood control facility, Sacramento River at
Benefits & Results:
- Our firm's practical experience and deep knowledge base helps clients understand the potential hazards for their engineering works as a result of erosion in the natural environment.
- Our analyses and designs provide effective remedies for a wide range of problems related to erosion and sedimentation.