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management using hydraulic roughness. Modern river engineers do not habitually minimize hydraulic roughness, they effectively use it as a design tool. Rough points created by designed structures or designed vegetation direct flow away from vulnerable areas. Strategic use of hydraulic roughness also dissipates energy and generally lowers the stress on bed and banks. This simple and useful insight is one compelling reason why old style "hard armor" has such a limited role in stream management. Changes in channel profile are accomplished using grade structures constructed of rock, logs, woody debris or manufactured products. Grade structures are particularly useful in arresting incision (downcutting). At-grade struc- tures stop incision at the existing channel elevation. El- evated, in-series, grade structures can reverse the incision and re-establish the pre-disturbance bed elevation and slope. These elevated grade structures modify the effective bed slope with commensurate influences on sediment transport and flow capacity. These channels self heal as the sediment is redeposited and bank heights decrease reducing the risk of bank failures. Properly designed and installed elevated grade controls can equilibrate the stream system hydrology, hydraulics and sediment load following dam removal or re- orientating astraightened stream to a meandering course. These approaches of grade control are highly effective but not simplistic; the cookie-cutter application is far less likely to succeed. In flash-flood prone urban streams, flood capacity must be maintained. Moreover, while the primary purpose of grade structures is managing channel slope, the location in plan form is critical as is the spacing within a series of structures. In stable streams, hard points (riffles) occur at the point of inflection in the meander waveform. Misplaced hard points can reset a stream's meander pattern and induce widespread erosion. Not only can misplaced grade structures unwittingly reset the watershed-wide meander geometry; structures that locally change plan form can have similar impacts. These structures include mis- shaped riprap slopes, poorly placed or constructed retaining walls and progressively failing storm water pipe outfalls. The deliberate adjustment of plan form using hard points is sometimes called remeandering. The objective of remeandering is to restore equilibrium between channel slope, width and wavelength. Otto Franzius described the methodology in the early 20th century. Once a stable waveform is determined from geomorphology diagnosis and analysis, the remaining elements of stream geometry are iteratively balanced to this form. In addition to achieving stable streams capable of competently transporting the supplied water and sediment, stream planform geometry can 1 :, r ~ r { ~ ~: ,~ ' i ~~x~+x,~„ -~ ~„~~ ,~~~~ ~, mow, ~ "~'~ ~,~~~ i ~, a .. ~ ~~ ~ - .~ ; .r.r:; Y "~`t ~,~~ Via- , - f ~ . _ ~ ~~ . ._ _ r ~ -,... s `, , ~ t ,_ _~ ~+~> -k~-~n,,.~ - - 4 ti ., ,t - a - 1 ~ r t :: s. ;T a T r , ~, '' : r r':'~ ~ v ~ ~ F _ .~__.~ r .(3 T ~f A ~ ..err ~; ~ia ~ ~?L., ~ ` .1 ' ~~ _ ~ be explicitly designed to reduce stress on bridge piers, culvert crossings and other infrastructure. In summary, the approach of modern river design firms is to evaluate the fundamental stability of rivers and streams. We, as design. engineers and scientists with extensive expe- rience in landform analysis, fluvial science, resource management and engineering, analyze problem areas as elements of a whole and not in isolation. This more sys- tematic approach avoids causing new problems in the attempt to address the old ones. Greater stability of the system is achieved and costs are better managed. Our approach permits less intrusive designs such as proven soil bioengineering techniques that return streams to a more normal function. Because of our sound fundamental science, our designs and recommendations are fully defen- sible to the client, public and regulatory agencies. Editors Note. Intuition & Logic will be presenting an ADA Technical Seminar on Bio-Engineering at the MAWD Annual Meeting. 15