WSP08097

• File Number: 8507
• Description: Rio Grande Project
• State: CO
• Basin: Rio Grande
• Date: 2/1/1961
• Title: Final Report Hydralic Model Studies
• Water Supply Pro - Doc Type: Report/Study

I :;
! ~;..1
, g;
".J

CONCLUSIONS

{j

structure

'..-.,

The results of the model studies showed that Weir G (the cross

section of which is shown in Fig. 8) would be suitable for use in the

Rio Grande as a control and measuring structure. Modification of the

sloping faces of the weir flatter than 2:1 and 3:1 for the upstream and

;~:;;

downstream slopes, respectively, did not improve the hydraulic per-

tr:;

formance of the structure. The crest of the structure should be wide

~.~~

enough, parallel to the flow, for the establishment of a good measur-

ing section. For unit discharges up to 25 cfs per ft, 10 ft would be

sufficient, but wider structures may be used. Measurements of discharges

':;'

and stages should be made within the middle third of the structure. The

recommended height of sill is one foot above the crest of the weir. (See

Fig. 8.) This height will allow control to be maintained at the sill and

create sufficient velocities over the crest of the structure at low dis-

Charges for measurement With a current meter. The elevation of the top

,

of the sill with respect to tailwater level must be estabJ.ished with

adequate field information on stage discharge relations at the site. Use

of Fig. J.9 will assist in the establishment of the sill level.

stage-Diecharge Relation

The stage-discharge rating at the structure is unaffected by upstremm

channel aggradation so long as the bed does not Bggrade above the crest of

the structure. It is affected, however, at any unit discharge by changes

in tailwater level if the submergence is greater than about 60 percent.

-33-

'l-'l :I~, "~
I-....*,,-.. ~""'