Rational Method Link-Node Modeling

Model Modes
a. Basic Mode (without Coupled Street Modules)
b. Intermediate Mode (with Coupled Street Modules)
c. Advanced Mode (Integrated Rational and Unit Hydrograph Method with Coupled Street Modules)
d. GIS Mode (GIS Data Base Interface)
Metric
Detailed Output
Form Output
Schematic
Multiple Path Confluence Analysis
GIS Interface
SIMS
Global Editor
a. Globally Change a Manning’s friction factor for All Computer Estimated Pipesize Processes
b. Change All User-Specified Pipesize Processes to Computer Estimated Pipesize Processes
c. Globally Change All Streetflow Depth (w.r.t. top-of-curb) Constraints (Intermediate/Advanced Mode)
d. Globally Change All Streetflow Depth*Velocity Constraints (Intermediate/Advanced Mode)

RATional Method Hydrology Applications.

This computer application enables the program user to create a Master Plan or design a watershed system interactively. The watershed is split into several subareas by the designer. The study proceeds in a sequential manner in the downstream direction. The designer selects from a menu of possible hydrologic submodels to describe the watershed characteristics in each subarea. The program prompts the user for all the necessary information regarding watershed subarea characteristics and computes hydraulic and hydrologic information. The designer then reviews the hydrologic results as to acceptability and options whether to proceed with the design or investigate an alternate hydrologic process in the subject subarea. This review is accomplished at each link and nodal point and enables the designer to use the computer as a design tool interactively rather than in a "batch" mode. The watershed master planned system is stored in computer memory which can be easily changed, updated, or restudied with respect to other hydrologic criteria (e.g., 10, 25, 100-year return events).

Due to the speed of computers, hydraulic and hydrologic approximations are quickly determined, reducing the overall rational method hydrology study time expenditure. Estimated time savings for a study using the RATional Method Hydrology programs for the first time is about 30 percent. The program learning curve is reduced due to the user-friendly self-instructive page formats.The hydrology programs have been used to prepare more than 50 city or county wide master plans of drainage in Southern California, including Anaheim, Chino, Ontario, Yucaipa, Upland, Apple Valley (1991 California Council of Civil Engineers and Land Surveyors "Grand Award of Excellence" winner), Victorville, Huntington Beach, Rancho Cucamonga, Fontana, Hesperia, Big Bear, San Bernardino, Redlands, Loma Linda, Orange, Torrance, Laguna Niguel, County of San Joaquin, Imperial Irrigation District, among many others. The latest updates to our RATional Method Hydrology software features storm drain deficiency analysis, integrated unit hydrograph methodology (1994 release), and linkage to GIS (1995 release). Generation 3 programs are available for Kern, San Bernardino, San Joaquin, and Orange County Models.

Key Features

– Initial subarea time of concentration.
– User-specified Tc algorithm
– Computer-estimated pipesize pipeflow travel time:
– Coupled to streetflow
– Multiple streetflow constraints
– Computer-estimated box size box flow travel time:
– Coupled to streetflow
– Multiple streetflow constraints
– Stream confluence model:
– Memory bank modules
– All confluence evaluation algorithm
– Peak flow-rate tables
– Time-area analysis
– User-specified rainfall intensity as a function of duration:
– Log-log relationship
– Tabulated data
– Internal soil-loss charts:
– Automatic yield estimates
– Internal editor allows the program user to easily modify program information on a subarea basis or on a global basis.
– Output options:
– Detailed report
– County-specific rational method form
– Two types of link node schematics that visually show stream linkages and confluences
– Facility inventory and cost summary
– Integrated Unit-Hydrograph/Rational Method option, whereby both methods are available to compute peak flow rates.
– Specified pipesize pipeflow travel time:
– Surcharged flow
– Coupled to streetflow
– Specified box size box flow travel time:
– Surcharged flow
– Coupled to streetflow
– Trapezoidal channel flow travel time:
– Channel flow (Computer-estimated channel section and user-specified channel section.)
– Natural mountain flow
– Natural valley flow
– Addition of subarea to mainline model:
– Initial subarea with mainline Tc analysis
– User-specified hydrologic information at a point
– Peak flowrate table
– Streetflow travel time including "split-flow" model:
– Coupled to pipeflow option
– Computer results ready for drainage reports:
– Includes a detailed report or a rational method chart summary
– Internal computer tutor text which reviews for the user pertinent first-course hydrology information.
– Scratch Pad for parameter estimation and hydraulic calculations
– Metric and English units