Abstract:
CASC2D is a fully-unsteady, physically-based, distributed-parameter, raster (square-grid), two-dimensional, infiltration-excess (Hortonian) hydrologic model for simulating the hydrologic response of a watersheds subject to an input rainfall field. Major components of the model include: continuous soil-moisture accounting, rainfall interception, infiltration, surface and ... channel runoff routing, soil erosion and sediment transport. CASC2D development was initiated in 1989 at the U.S. Army Research Office (ARO) funded Center for Excellence in Geosciences at Colorado State University. The original version of CASC2D has been significantly enhanced under funding from ARO and the U.S. Army Corps of Engineers Waterways Experiment Station (USACEWES). CASC2D has been selected by USACEWES as its premier two-dimensional surface water hydrologic model, and is one of the surface-water hydrologic models support by the the Watershed Modeling System (WMS) under development at Brigham Young University.
CASC2D is a state-of-the-art hydrologic model that takes advantage of recent advances in Geographic Information Systems (GIS), remote sensing, and low-cost computational power. Compared with the USACE standard practice surface water hydrology model HEC-1, CASC2D offers significant improvements in capability. HEC-1 requires the division of study watersheds into sub-catchments that are assumed to be hydrologically uniform, while CASC2D allows the user to select a grid size that appropriately describes the spatial variability in all watershed characteristics. Furthermore, CASC2D is physically-based; CASC2D solves the equations of conservation of mass and energy to determine the timing and path of runoff in the watershed. More traditional approaches such as HEC-1 rely on more conceptualizations of runoff production. The physically-based approach is superior when the modeler is interested in runoff process details at small scales within the watershed. Physically-based hydrologic models are also superior when trying to predict the behavior of ungaged watersheds where calibration data do not exist.
CASC2D is fully spatially-varied at a user specified resolution (typ. 30-200 m) and therefore requires considerably more input data than HEC-1. Spatially-distributed modeling offers the capability of determining the value of any hydrologic variable at any grid-point in the watershed at the expense of requiring significantly more input than traditional approaches. CASC2D readily accepts spatially-varied input in any watershed or rainfall input, however, input data uncertainty may result in a non-unique calibration.
CASC2D has a large number of input and output options. The WMS interface for CASC2D is valuable because it separates the user from issues related to input file formatting, and guides the user through model set-up and option selection. WMS does not, and is not intended to, replace the full functionality of a Geographic Information System (GIS). The GRASS GIS developed by the U.S. Army Construction Engineering Research Laboratories is very helpful in the preparation of CASC2D data sets. CASC2D relies on the GRASS ASCII data file format for storing all spatially-distributed variables. The WMS interface can directly access data from both the ARC/INFO and GRASS GIS systems and export data to CASC2D.
Description:
The Watershed Modeling System (WMS) can now be obtained for public domain use - free of charge. This freeware version of the software will allow anyone to set up and execute a hydrologic model using the schematic set up option in the Hydrologic Modeling Module of WMS.
Use Constraints
Users with no background in or understanding of distributed hydrology are strongly advised against using this code in any mode, particularly in operational mode. Besides knowledge of basic hydrology, experience with typical numerical techniques used in physically-based hydrodynamic models is recommended as it will help the user grasp capabilities and ... limitations of this model. This manual is significantly condensed for electronic distribution and is in no way comprehensive. Users are encouraged to experiment with the model and venture in hydrology textbooks and journal papers to learn more about the topics touched upon in this manual. The r.hydro.CASC2D code is continuously being improved. Changes in the source code of r.hydro.CASC2D may be made at any time, without notification. No claims are made regarding the suitability of r.hydro.CASC2D for any particular purpose. The model r.hydro.CASC2D was written for research and educational purposes.
Name:
NINA
R.
COOPER
Phone:
860-486-2297
Email:
nan.cooper at uconn.edu
Contact Address:
School of Engineering
University of Connecticut
261 Glenbrook Rd., Unit 2237 City:
Storrs
Province or State:
CT
Postal Code:
06269-2237
Country:
USA
Personnel
TYLER
B.
STEVENS Role:
SERF AUTHOR
Phone:
(301) 614-6898
Fax:
301-614-5268
Email:
Tyler.B.Stevens at nasa.gov
Contact Address:
NASA Goddard Space Flight Center
Global Change Master Directory City:
Greenbelt
Province or State:
MD
Postal Code:
20771
Country:
USA
FRED
L.
OGDEN Role:
TECHNICAL CONTACT
Phone:
860-486-2771
Fax:
860-486-2298
Email:
ogden at engr.uconn.edu
Contact Address:
University of Connecticut
School of Engineering
261 Glenbrook Rd., Unit 2237 City:
Storrs
Province or State:
CT
Postal Code:
6269
Country:
USA
Publications/References
Bras, R. L., 1990, Hydrology: An introduction to hydrologic science, Addison-Wesley, Reading, Mass., 643 p.
Crum, T. D., and R. L. Alberty, 1993, The WSR-88D and the WSR-88D operational support facility, Bulletin of the American Meteorological Soc., 74(9), pp. 1669-1687.
Cunge, J.A., F.M. Holly, and A. Verwey, 1980, Practical Aspects of ... Computational River Hydraulics, Iowa Institute of Hydraulic Research, 404HL The University of Iowa, Iowa City, IA 52242. 420 p.
Gray, D.M., 1970, Handbook on the Principles of Hydrology, National Research Council of Canada, Water Information Center Inc., Water Research Building, Manhasset Isle, Port Washington, N.Y., 11050.
Julien, P. Y., and B. Saghafian, 1991, CASC2D users manual - A two dimensional watershed rainfall-runoff model, Civil Engr. Report, CER90-91PYJ-BS-12, Colorado State University, Fort Collins, CO.
Julien, P. Y., Saghafian, B., and F. L. Ogden, 1995, "Raster-Based Hydrologic Modeling of Spatially-Varied Surface Runoff", Water Resources Bulletin, AWRA, 31(3), pp. 523-536.
Ogden, F.L., 1994, de-St Venant channel routing in distributed hydrologic modeling., Proc. Hydraulic Engineering `94, ASCE Hydraulics Specialty Conference, G.V. Cotroneo and R.R. Rumer, eds., Vol. 1, pp. 492-496.
Ogden, F.L., Saghafian, B., and W.F. Krajewski, 1994, GIS-based channel extraction and smoothing algorithm for distributed hydrologic modeling, Proc. Hydraulic Engineering `94, ASCE Hydraulics Specialty Conference, G.V. Cotroneo and R.R. Rumer eds., August 1-5, 1994, Buffalo, N.Y., pp. 237-241.
Rawls, W. J., Brakensiek, D. L., and N. Miller, 1983, Green-Ampt infiltration parameters from soils data, J. of Hydraulic Engineering, ASCE, 109(1), pp. 62-70.
Rawls, W. J., Brakensiek, D. L., and K. E. Saxton, 1982, Estimation of soil water properties, Trans. of ASAE, pp. 1316-1320.
Saghafian, B., 1992, Hydrologic analysis of watershed response to spatially varied infiltration, Ph.D. Dissertation, Civil Engr. Dept., Colorado State University, Fort Collins, CO.
Saghafian, B., 1993, Implementation of a distributed hydrologic model within Geographic Resources Analysis Support System (GRASS), Proceedings of the Second International Conference on Integrating Environmental Models and GIS, Breckenridge, CO.
Smith, R. E., Corradini, C., and F. Melone, 1993, Modeling infiltration for multistorm runoff events, Water Resources Research, 29(1), pp. 133-144.
Creation and Review Dates
SERF Creation Date:
2004-09-02
SERF Last Revision Date:
2008-10-01
Links
