crwr-prepro: a system of gis tools for hec-hms modeling support
DESCRIPTION
19th ESRI International User Conference Water Resources Rainfall Runoff Modeling Using GIS and HEC-HMS July 25, 1999 - San Diego, California. CRWR-PrePro: A System of GIS Tools for HEC-HMS Modeling Support. Francisco “Paco” Olivera, Ph.D. Center for Research in Water Resources - PowerPoint PPT PresentationTRANSCRIPT
CRWR-PrePro: A System ofGIS Tools for HEC-HMS Modeling Support
Francisco “Paco” Olivera, Ph.D.Center for Research in Water Resources
University of Texas at Austin
19th ESRI International User ConferenceWater ResourcesRainfall Runoff Modeling Using GIS and HEC-HMSJuly 25, 1999 - San Diego, California
The Team
David Maidment, Ph.D. Seann Reed, Ph.D. Ximing Cai, Ph.D. Ferdinand Hellweger Aubrey Dugger Francisco Olivera, Ph.D.
How many Ph.D.’s do you need to develop CRWR-PrePro?
What is HEC-HMS?
“It is a new generation software for precipitation-runoff simulation that supersedes the HEC-1 Flood Hydrograph Package.” (HEC-HMS User’s Manual)
It is a Windows version of HEC-1.
HEC-HMS Input Components
ControlDefinition of the analysis
time window.
PrecipitationDefinition of rainfall data
in time and space.
BasinDefinition of the
hydrologic elements of the system.
HEC-HMSSimulation
What is CRWR-PrePro?
Digital Spatial Data
Data for HEC-HMS Input Components
(Not all HMS options are included yet)
CRWR-PrePro
Overview
Input Data for the HEC-HMS Basin Component Raster-Based Terrain Analysis Raster-Based Sub-Basin and Reach Network Delineation Vectorization of Sub-Basins and Reach Segments Computation of Hydrologic Parameters of Sub-Basins and
Reaches Extraction of Hydrologic Sub-System Topologic Analysis
Input Data for the HEC-HMS Precipitation Component User-Specified Gage Weighting GridParm
Terrain Analysis
71
56
445369
74
78 72 69
4768
58 55
21
31
67
58
49 46
37 38
64 22
61 16
Digital elevation model (DEM)
22
2 2 2
2
4 4
4 4
1 1 2 4 8
128
128 1 2 4
128 1 41
128
Flow direction grid Flow accumulation grid
0 0 0 0 0
0 1 1 2 1
0
0
0 0 0
3 8 5 2
1 1 20 0
1 24
Stream Network
Flow direction codes
1
248
16
32 64 128
Hydrologic functions
Terrain Analysis
45
44
38
34
40
45
50
60
58
31
30
53
50
45
32
22
DEM creek
45
44
38
34
40
45
50
60
58
31
30
53
50
45
32
22
Digitized creek
38
34
30
22
Digitized creek
145
144
138
134
140
145
150
160
158
131
130
153
150
145
132
122
Raised DEM
145
144
38
34
140
145
150
160
158
131
30
153
150
145
132
22
Burned-in DEM
Burning-in streams
Terrain Analysis
DEM and digitized reach network
Terrain Analysis
Burned-in DEM
Elevation is increased by a fixed value in all cells, except for those that coincide with the digitized reach network.
Terrain Analysis
Flow direction
Water flows to one of the eight neighbor cells, according to the direction of the steepest descent.
Terrain Analysis
Flow accumulation
Measure of the drainage area in units of grid cells.
Sub-Basins and Reach Network
Reach network.
Grid cells draining more than a user-defined threshold value (blue streams), or located downstream of user-defined cells (red streams) are part of the reach network.
Sub-Basins and Reach Network
Reach segmentation.
Reach segments (links) are the sections of a reach channel connecting two successive junctions, a junction and an outlet, or a headwater and a junction.
Sub-Basins and Reach Network
Watershed outlets.
The most downstream cells of the reach segments (brown cells), and user-defined cells (red dots) are potential sub-basin outlets.
Sub-Basins and Reach Network
Modified reach segmentation.
The user-defined outlets modify the reach segmentation by splitting the segments in which they are located.
Sub-Basins and Reach Network
Sub-basin delineation.
The drainage area of each sub-basin outlet is delineated.
Vectorization
Streams and watersheds are converted from raster to vector format.
Vectorization
Adjacent watershed polygons can be merged into a single polygon, if they share the outlet or one flows into the other.
Vectorization
After merging sub-basin polygons, the attribute tables are modified so that the watershed code (WshCode) of the reaches and the area of the new sub-basin are updated.
Hydrologic Parameters
Flow length downstream to the sub-basin outlet.
Hydrologic Parameters
Flow length upstream to the sub-basin divide.
A NODATA cell is defined at the sub-basin outlets before running the flow length function.
Hydrologic Parameters
Sub-basin longest flow-path.
The longest flow-path is the geometric locus of the points for which the sum of both flow lengths is a maximum.
Hydrologic Parameters
t5.3,
S67.31
]9)CN/1000[(Lmaxt
5.0
7.08.0w
p
tp: sub-basin lag-time (min)LW: length of sub-basin longest flow-path (ft)CN: average Curve Number in sub-basinS: slope of the sub-basin longest flow-path (%)t: analysis time step (min)
Sub-basin lag-time according to the SCS formula:
Hydrologic Parameters
t5.3,
V60
L3048.06.0maxt
w
wp
tp: sub-basin lag-time (min)Lw: length of sub-basin longest flow-path (ft)Vw: average velocity sub-basin longest flow-path (m/s)t: analysis time step (min)
Sub-basin lag-time according to 0.6 L/v formula:
Hydrologic Parameters
Sub-basin parameters: Grid code, area (Km2), unit hydrograph model (SCS), length of longest flow path (m), slope of longest flow path (fraction), average curve number, lag-time (min), baseflow (none).
Hydrologic Parameters
s
slag V60
Lt
tlag: reach lag-time (min)Ls: length of reach (m)Vs: reach average velocity (m/s)
Reach lag-time for Pure Lag routing:
Hydrologic Parameters
s
s
V3600
LK
K: Muskingum parameter K (hr)X: Muskingum parameter XLs: reach length (m)Vs: reach average velocity (m/s)n: number of sub-reaches
1t
V60/LX2intn ss
Reach lag-time and number of sub-reaches for Muskingum routing:
Hydrologic Parameters
Pure lag routing for Ls/60vs < t, otherwise Muskingum routing.
Reach parameters: Grid code, sub-basin code, length(m), velocity (m/s), routing method (Lag or Muskingum), lag time (min), Muskingum X, Muskingum K (hr), number of sub-reaches.
Hydrologic Sub-System
Manual selection of sub-basin polygons
Hydrologic Sub-System
Manual selection of most downstream sub-basin polygon.
Topologic Analysis
HEC-HMS schematic in ArcView.
Topologic Analysis
HEC-HMS schematic in HMS.
Topologic Analysis
Overview
Input Data for the HEC-HMS Basin Component Raster-Based Terrain Analysis Raster-Based Sub-Basin and Reach Network Delineation Vectorization of Sub-Basins and Reach Segments Computation of Hydrologic Parameters of Sub-Basins and
Reaches Extraction of Hydrologic Sub-System Topologic Analysis
Input Data for the HEC-HMS Precipitation Component User-Specified Gage Weighting GridParm
User-Specified Gage Weighting
Intersection of sub-basin polygons with gage Thiessen polygons.
User-Specified Gage Weighting
Precipitation in each sub-basin is calculated as a weighted average of the precipitation in the gages.
User-Specified Gage Weighting
Precipitation model in HEC-HMS
GridParm
Precipitation cells for modClark sub-basin routing.
GridParm
Precipitation cells for modClark sub-basin routing.
Conclusions
CRWR-PrePro pre-processes digital spatial data and produces input data for the HEC-HMS basin and precipitation components.
CRWR-PrePro supports six of the seven hydrologic elements used in HEC-HMS. Within these elements it supports the SCS unit hydrograph for sub-basin routing, pure lag and Muskingum for reach routing, curve number and initial-plus-constant for precipitation excess calculations.
CRWR-PrePro supports the user-specified-gage-weighting and GridParm for spatial interpolation of precipitation data.
Basin FileWatershed Parameters
Basin FileWatershed Parameters
Basin FileStream Parameters
Precipitation File
Control File
Hydrograph Time Table
Hydrograph Summary
Hydrograph Plot