Stream and wetland restoration is the process in which an impacted area is evaluated and restored to a natural condition that may have existed within that area prior to the impact. Stream, wetland, and buffer restoration projects begin with a thorough investigation of the existing conditions of the project site and its surrounding watershed. Streams are evaluated for priority restorations with reconnection to the floodplain as the ultimate goal. Streams are designed for the hydraulic capacity of bankfull conditions. A Priority One stream restoration puts back the natural pattern, profile, and section of an impaired stream.
Ward Consulting Engineers have successfully completed rural and urban streams and wetland restoration projects in North Carolina. The projects have been completed with clients such as the North Carolina Ecosystem Enhancement Program, the City of Raleigh, and the North Carolina Department of Transportation (NCDOT). Unlike rural sites, urban projects require a comprehensive understanding of natural channel design as well as hydraulic design to evaluate the potential that additional structural measures may be required in confined areas. Urban projects also involve limited access and unique construction considerations. Ward Consulting Engineers has experience in both the rural and urban settings.
Ward Consulting Engineers has staff professionals with advanced degrees in Water Resources and Rosgen natural channel restoration training through Level IV.
Ward Consulting Engineers Provides the Following Services:
Stream and Wetland Assessment
An inventory of the physical characteristics of the stream corridor and wetland area provides invaluable baseline data. The assessment quantifies the current state of the stream and to make inferences in trends as to the streams future condition. Assessment data is used to establish correlations between the stream and wetlands present condition and its deviation from stable conditions.
Stream and Wetland Inventory
An inventory is conducted to determine problem areas, quantify the degree and extent of existing erosion problems, and prioritize any required remedial actions. This information can then be transferred to a base map that provides an overall visual view of problem areas. This map can be used to identify high-risk areas for priority determinations and as a planning tool for the watershed and future easement acquisition.
Channel Stability Measurements
Channel stability measurements to determine vertical bed stability, lateral bank stability, and bed material size distribution are made to estimate sediment-loading rates from stream bank erosion, vertical movement of the stream channel and bed material changes. Channel stability measurements assist in the analysis of potential causes of habitat disturbance.
Detailed Stream Reach Analysis & Design
Typically one to two cross sections per 1,000 linear feet are needed to characterize the stream. Cross sections typically are established along the existing stream, located in riffles, runs, pools or glides. Riffle cross sections are surveyed to determine the bankfull cross sectional area, width/depth ratio, maximum depth, mean depth, flood prone area, and entrenchment ratio. The longitudinal profile (riffle/pool sequences, channel, water surface and bankfull slope, pool to pool spacing, riffle, run, pool, and glide slopes and lengths) are developed from the topographic survey, pebble counts undertaken and the bankfull stage is determined. The stream’s pattern is measured either from topographic mapping or on-site and includes belt width, sinuosity, meander length, and radius of curvature. A stable reference reach is identified and evaluated with a detailed stream reach analysis, which is used as a model for the proposed stream design.
Wetland Evaluations & Design
Reference wetlands are evaluated to determine the biology, hydrology, water chemistry, soil, and sediment characteristics. Water saturation (hydrology) largely determines how the soil develops along with plant and animal communities living in and on the soil. A water budget is established to determine available water input to the proposed wetlands. The targeted hydrology for the site is developed and the proposed site is evaluated as to the topographic conditions needed on the site to achieve wetland hydrology. Many wetlands are seasonal, the quantity of water present and the timing of its presence in part determines the design and functions of the wetland.