How do you calculate overland flow distance?
If the catchment area is symmetrically distributed around the drainage network, an approximate value for the overland flow length can be found by dividing the area by twice the length of the drainage channel.
How do you calculate sheet flow?
Narrative: The calculation of overland flow (sheet flow) length by equation 1 requires the sum of stream lengths and area of the watershed to be in consistent units. For example, if Dd is 48,900 feet, the area of the watershed also should be in square feet or 206 acres times 43,560 square feet per acre.
What is TC in hydrograph?
Time of concentration (Tc) is the time required for runoff to travel from the hydraulically most distant point in the watershed to the outlet.
What is catchment harvesting?
1. Catchments: The catchment of a water harvesting system is the surface which directly receives the rainfall and provides water to the system. Channels all around the edge of a sloping roof to collect and transport rainwater to the storage tank.
How do you calculate rainfall volume?
Find the average volume of rain = Depth x radius x radius x 3.14. Find the area at the top of the bucket (this is the area over which the rain is collected).
How did KIRPICH come up with the TC equation?
Kirpich’s equation (1940) was developed for small, agricultural watersheds. It was derived by examining the required time for the stream to rise from low to maximum stage during a storm. The time of concentration was then assumed equal to that time. tc = time of concentration in hours. L = length of the overland flow in feet.
How is KIRPICH’s equation for time of concentration derived?
Kirpich’s equation (1940) was developed for small, agricultural watersheds. It was derived by examining the required time for the stream to rise from low to maximum stage during a storm. The time of concentration was then assumed equal to that time. tc = time of concentration in hours.
How to calculate the KIRPICH formula for drainage?
Kirpich Formula Calculations. t ch = time of concentration (minutes) K = a units conversion factor taken as 0.0195 for Si units or 0.0078 for US units. L = channel flow length (m) S = dimensionless main channel slope.
How is the KIRPICH formula used in surface runoff design?
The Kirpich Formula is used to estimate the time of concentration used in surface runoff design. The Kirpich equation was developed in 1940 from a study of 7 small (1.25 acres – 112 acres) rural catchments in Tennessee with well-defined channels and steep slopes (3%-10%).