Three models were used to study portions of the high-velocity reaches within the Rio Puerto Nuevo basin. A 1:35-scale model of the Puerto Nuevo Channel was tested to determine the flow conditions in the transitions and curves in the supercritical channel, at the junctions with the Guaracanal Channel and Buena Vista Diversion Channel, at the bridges, and in the reach of channel where the flow transitions from supercritical to subcritical flow. Tests were conducted on a 1:25-scale model of the Josefina Channel to determine the flow conditions at the junction with the Dona Ana Channel and where the flow transitions from supercritical to subcritical flow. A 1:35-scale model of the Margarita Channel was also studied to determine the flow conditions in the vicinity of the De Diego Expressway Bridge and where the flow transitions from supercritical to subcritical flow. It is expected that the prototype flow geometry and boundary conditions in the Puerto Nuevo Channel will result in a Manning's n value approximately equal to 0.015. However, flow conditions resulting from a Manning's n value of 0.012 were also documented so that an envelope of possible hydraulic conditions could be established. In the absence of standing waves, water-surface elevations were slightly higher with the larger n value. Flow velocities were slightly higher and standing waves created by disturbances were significantly higher with the smaller n value. The recommended design incorporates into the original proposed design straightening the channel walls from sta 205+57.70 to 204+86.94, extending the Puerto Nuevo Channel/Buena Vista Diversion Channel confluence wall 70.76 ft downstream, adding debris noses on the Pinero Avenue Bridge piers, extending the Las Americas Expressway Bridge piers upstream to sta 158+53.85, and adding two rows of 10-ft-high by 10-ft-wide baffle blocks followed by six rows of 4-ft-high by 4-ft-wide baffle blocks between sta 150+40 and 148+34. The confluence of the Josefina and Dona Ana Channels provided an appropriate transition to converge the flow of the two channels. An oblique standing wave observed downstream of the confluence did not cause adverse effects downstream and was considered acceptable. Curves in the proposed design maintained acceptable water-surface elevations throughout the test section. The grade breaks (16+20 and 15+00) from a mild to a steep to a very mild slope forced a hydraulic jump for all test conditions and were determined to be a satisfactory design. The proposed design as tested is the recommended supercritical channel design to provide rapid transit for floodwaters in the low-lying area. Tests conducted with the Margarita Channel model to determine the flow conditions in the vicinity of the De Diego Expressway Bridge indicated that the original design passed discharges less than or equal to 9,900 cfs under the bridge. The original design resulted in unacceptable flow conditions in the transition reach of the channel. The type 7 design transition, which consisted of a 1V on 8H transition flare in conjunction with a 3.25-ft-high sill placed at an angle on the channel invert between sta 52+77 and 52+50, was the best transition tested for distributing the flow in the transition across the channel width.


    Access

    Download


    Export, share and cite



    Title :

    Rio Puerto Nuevo Flood Control Project, San Juan, Puerto Rico: Hydraulic Model Investigation



    Published in:

    Publication date :

    1990


    Size :

    8166827


    Type of media :

    Report


    Type of material :

    Electronic Resource


    Language :

    English



    Classification :