Show work You are the City Engineer for the municipality of

Show work

You are the City Engineer for the municipality of Paradise, Montana. Lunker Creek flows through your fair city and, unfortunately, receives an extremely high sediment load from unstable upstream reaches. You decide to perform a historical analysis and geomorphic assessment of Lunker Creek with the hope of determining the source(s) of excess sediment causing aggradation problems in Paradise. By using aerial photos, talking with landowners and agricultural agency personnel, and walking the stream (with landowner permission!), you learn that the high sediment load in Lunker Creek is primarily derived from a reach that has been historically overgrazed and subsequently channelized by the NRCS (formerly the SCS). The relocated / channelized reach has incised through a 2 m surface layer of gravel into lacustrine silt. In some locations the channel has dropped 5-8 meters. Luckily this reach is associated with a single landowner, and you and local agency folks write a Clean Water Act §319 grant proposal and obtain funding to restore the problematic section. A rough drawing of the situation is provided below. The landowner will only agree to the work if you keep his house “next to the water” (hint: it doesn’t have to be a lotic ecosystem that the house is adjacent to). Your task is to develop a preliminary restoration plan for a stable meandering channel that initiates motion of the median bed material diameter (54 mm) at 80% of the bankfull depth. Assume a *c of 0.033. The design discharge is 360 cfs and the valley slope is 1%. Appropriate at-a-station and downstream hydraulic geometry relationships for the design reach are h µ Q 0.44 and w = 2.3Q 0.50 (English Units of feet and cfs), respectively. For the preliminary design, simplify matters by assuming a rectangular channel with w/h = 20 (bankfull) and R = h.a) Report your preliminary design width, sinuosity, meander wavelength, and rc/w.b) At what percentage of bankfull discharge should motion of the gravel initiate?c) How could you provide a suitable water body next to the landowner’s house? How might you get the material to fill in the old channel? (Hint: think about natural features created on the floodplain by meandering channels.)d) Based on van den Berg’s approach, is the slope reasonable for a meandering channel?e) How might your historical analysis help you determine if this is a reasonable sinuosity?f) What would you be sure to ask of the landowner and write into the Clean Water Act proposal to ensure the sustainability of the project?

Solution

a.)To solve this we use Manning\'s equation and also Q=A*V.Please do showthe hydraulic geometry relations clearly.

The drawing is also not given