SURFACE-WATER FIELD TECHNIQUES

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Boundary Creek near Porthill, Idaho - n = 0.073

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Site Description

 

Station name	Boundary Creek near Porthill, Idaho
Station number	12-3215
Gage location	Lat 48°59'50'', long 116°34'05'', in SW 1/4 sec. 11, T. 65 N., R. 2 W., on left bank near muoth of canyon 0.2 mile south of international boundary, and 3 miles west of Porthill. Section 1 is about 413 ft upstream from gage.
Drainage area	97 sq mi, approximately.
Date of flood	May 28, 1948
Gage height	5.34 ft at gage; 13.60 ft at section 1
Peak discharge	2,530 cfs
Computed roughness coefficient	Manning n = 0.073
Description of channel	Bed consists of boulders; d50 = 210 mm, d84 = 375mm. Banks are composed of boulders and have trees and brush along top.

Introduction Page || Site Description || Reach Properties
Plan Sketch and Cross Sections || Site Photos

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Reach Properties

 

Section	Area (sq ft)	Top Width (ft.)	Mean depth (ft)	Hydraulic radius (ft)	Mean velocity (ft per sec)	Lenght (ft) between sections	Fall (ft) between sections
1	351	64	5.48	4.87	7.21	.......	.....
2	338	82	4.12	3.93	7.49	94	1.45
3	327	71	4.61	4.09	7.74	163	3.95
4	400	118	3.39	3.30	6.32	177	2.70

Introduction Page || Site Description || Reach Properties
Plan Sketch and Cross Sections || Site Photos

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Plan Sketch and Cross Sections

Introduction Page|| Site Description || Reach Properties
Plan Sketch and Cross Sections || Site Photos

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Site Photos