SETRIC, a Mathematical Model for Sediment Transport in Irrigation Canals - Sediment Transport in Irrigation Canals: A New Approach - page 175

- The model can include changes in the bottom level at the upstream
boundary of a canal section;
- The control sections are set at the downstream end of the main canal or
secondary canals; the structure at the downstream end sets directly the
water level downstream of the gate for the hydraulic computations;
- The network might include lateral inflow or outflow; these flows are
located at the downstream side of the gate;
- The variation in water supply can be attuned to the varying water
requirement and follows the changes in area and time.

6.2.4 Input and output data

Input data
The input and output data for the computation of the water flow and
sediment transport in downstream control are comparable to the input and
output data previously mentioned for the upstream control (Section 6.1.5):
- Simulation period
- Canal dimensions
- Canal bottom
- Sediment data
Some differences are found in:
- Design discharge : the discharge at the upstream boundary;
- Water level : the tail water level downstream of the gate (downstream
pond level); the tail water level will not change during one simulation
period.
- Main and lateral discharges : the location of the inflow ( + ) and

outflow ( ) is at the downstream side of the automatic gates; for

downstream control the tail outflow (

−

− ) and the tail water depth are

required;
- Control sections : the water level control at the downstream side of
the automatic gates includes the water level and the location of the
structure. The automatic gates are specified by one of the three types of
AVIS gates (200/375, 180/335 and 160/300) and the number of gates;
other data include the outflowing discharge, downstream pond level
and the decrement over the gate;
- Downstream control : the model computes the upstream water level
from the downstream water level; this upstream level will act as the
control level for the hydraulic computations of the next upstream
canal-reach; the automatic gate at the upstream side of the reach will
adjust the discharge to maintain the set point at the downstream side of
the gate.

Output data
The computer program presents the results of the water flow and sus-
pended sediment transport calculations in tables,

graphs or in files