The Subcatchment Data Editor displays catchment and runoff data for each catchment area in separate pages.
The pages will vary according to the runoff method.
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Option
|
Description |
|
Subcatchment Name |
The name of the subcatchment. |
|
Drainage Node |
The node the subcatchment drains into. |
|
Lock |
Option to lock the runoff area to the specified area value. |
|
Runoff Area (ha) |
The total contributing runoff area in hectares. The Runoff Area option will not be active when a subcatchment is selected, since the area is calculated from the subcatchment polygon. |
|
Option
|
Description |
|
Paved Area (%) |
The percentage of the sub-catchment that consists of impervious material. |
|
Paved Area Entry Time (min) |
The paved entry time is the time it takes the runoff from the paved area to run along a gutter with a hydraulic radius of 60mm and a Manning factor of 0.02 to the inlet. The overland flow time for the runoff to reach the gutter is assumed to be two minutes, which is added to the gutter travel time. Click ... to display the entry time calculator. |
|
Paved Depression Storage (mm) |
The average losses in millimetres due to surface irregularities in the paved area. |
|
Supplementary Area (%) |
The percentage of the sub-catchment that consists of impervious material, which discharges onto a permeable surface i.e. roofs that discharge onto a lawn. |
|
Grassed Entry Time (min) |
The time in minutes for a drop of water to travel from the furthest part of the grassed zone to a point on the contributing paved area, or to the stormwater inlet if the contributing paved area is zero. |
|
Grassed Depression Storage (mm) |
The average losses in mm due to surface irregularities. |
|
Soil Type |
The soil classification which will determine the rate of infiltration. |
|
Option
|
Description |
|
Subcatchment |
The name of the subcatchment. |
|
Drainage Node |
The node this subcatchment drains to. Click on the right of the field to display a list of node names. |
|
Lock |
Option to lock the runoff area to the specified area value. |
|
Runoff Area (km2) |
The total contributing runoff area in square kilometres. The Runoff Area option will not be active when a subcatchment is selected, since the area is calculated from the subcatchment polygon. |
|
Option
|
Description |
|
Time of Concentration (hours) |
The time it takes for a drop of water to travel from the most distant part of the catchment to the catchpit. Click ... to display the Time of Concentration calculator. |
|
User Specified Point Rainfall |
Select if the Rational Runoff calculations must not calculate the Point Rainfall value from the standard Rational Runoff graphs but must make use of the entered value. |
|
Catchment Characteristics |
|
|
Rural Percentage |
The rural portion of the catchment area, expressed as a percentage of the total area. |
|
Rural Factor |
The rural area runoff coefficient which can be calculated using the rural coefficient calculator. |
|
Urban Percentage |
The urban portion of the catchment area, expressed as a percentage of the total area. |
|
Urban Factor |
The urban area runoff coefficient, which can be calculated using the urban coefficient calculator. |
|
Lakes |
The percentage of the catchment area consisting of lakes or ponds which do not contribute to runoff. |
|
Option
|
Description |
|
Subcatchment |
The name of the subcatchment. |
|
Drainage Node |
The node this subcatchment drains to. Click on the right of the field to display a list of node names. |
|
Lock |
Option to lock the runoff area to the specified area value. |
|
Runoff Area (km2) |
The total contributing runoff area in square kilometres. The Runoff Area option will not be active when a subcatchment is selected, since the area is calculated from the subcatchment polygon. |
|
Option
|
Description |
|
Percentage Impervious Catchment (PIMP) |
The percentage of the catchment area covered by impervious surfaces intended to drain to the storm sewer. |
|
Time of Entry (min) |
The time it takes for a drop of water to travel from the most distant part of the catchment to the catchpit. Click ... to display the Time of Entry calculator. |
|
Previous Pipe Length (m) |
The length of pipe between the upstream sub-catchment and this sub-catchment. |
|
Previous Pipe Velocity |
The calculated flow velocity in the pipe between the upstream sub-catchment and this sub-catchment. |
|
Time of Flow (min) |
The time of flow through the previous pipe to the point under consideration. Calculated from the pipe length and velocity. |
|
Time of Concentration |
The time of concentration is equal to the sum of the time of entry and the time of flow. |
|
Soil Type |
The soil index SOIL is based on the Flood Studies Report and can be obtained from the revised soil map covering the whole of the United Kingdom. The index takes one of the values 0.15, 0.3, 0.4, 0.45, 0.5, according to the five soil types 1 to 5 respectively. |
|
Option
|
Description |
|
Subcatchment |
The name of the subcatchment. |
|
Drainage Node |
The node this subcatchment drains to. Click on the right of the field to display a list of node names. Click ... to display the Node data of the Drainage node. |
|
Description |
A description of this subcatchment. |
|
Lock |
Option to lock the runoff area to the specified area value. |
|
Runoff Area (km2) |
The total contributing runoff area in square kilometres. The Runoff Area option will not be active when a subcatchment is selected, since the area is calculated from the subcatchment polygon. |
|
Width (m) |
Specify the characteristic width of the overland flow path for sheet flow runoff. |
|
Slope (%) |
Specify the average slope of the subcatchment as a percentage. |
|
Rain Gage |
Select the name of the rain gauge associated with this subcatchment from the dropdown list. Click ... to display the Rain Gauge Editor. |
|
Infiltration |
Displays the selected infiltration method that controls how infiltration of rainfall into the upper soil zone of subcatchments is modelled. The infiltration method is set in the Simulation Options. Click ... to display the Infiltration Editor. |
|
Groundwater |
Displays YES or NO to indicate the existence of groundwater flow. Click ... to edit groundwater flow parameters for the subcatchment in the Groundwater Flow Editor. |
|
Snow Pack |
Select the name of the snow pack associated with this subcatchment from the dropdown list. Click ... to edit the snow pack parameters in the Snow Pack Editor. |
|
Option
|
Description |
|
Impervious |
|
|
Area (%) |
Percentage of land area which is impervious. |
|
Roughness (N) |
Manning's n for overland flow over the impervious portion of the subcatchment. |
|
Depression Storage (mm) |
Depth of depression storage on the impervious portion of the subcatchment. (Typical Values) |
|
Pervious |
|
|
Roughness (N) |
Manning's n for overland flow over the pervious portion of the subcatchment. |
|
Depression Storage (mm) |
Depth of depression storage on the pervious portion of the subcatchment. (Typical Values) |
|
Subarea |
|
|
% Zero Impervious |
Percentage of impervious area with no depression storage. |
|
Subarea Routing |
Choice of internal routing of runoff between pervious and impervious areas:
|
|
Percent Routed |
Specify the percentage of runoff routed between subareas. |
|
Option
|
Description |
|
Land Uses |
Displays how many land uses are associated with this subcatchment. Click ... to display the Land Use Assignment window. |
|
Initial Buildup |
Displays YES or NO to indicate the existence of an initial buildup of pollutants. Click ... to display the Initial Pollutant Buildup window. |
|
Curb Length (m) |
Specify the curb length in the subcatchment associated with the pollutant buildup. |