Sediment Transport in the Colorado River and All-American Canal system at Imperial Dam
Like many other dams, Imperial Dam impounds much of the suspended sediment moving in the Colorado River but some of that suspended sediment makes its way to the All-American Canal, a major diversion for irrigation and municipal water. Water entering the All-American Canal is settled in several desilting basins to remove most of the remaining suspended sediment. The collected sediment from the desilting basins flows into the California Sluiceway and builds up until sluicing flows transport the sediment downstream into the Colorado River. At this time, the rate of sediment accumulation in the Sluiceway is not known. The timing of these sluicing events could be improved if sufficient suspended-sediment data was collected to determine this rate. Optimally scheduled sluicing events will ensure the most efficient use of Colorado River water to maintain the channel conditions of the California Sluiceway into the Colorado River.
The Imperial Dam Sediment project monitors the transport of suspended sediment from the All-American Canal desilting basins to the California Sluiceway below Imperial Dam and from the sluiceway downstream in the Colorado River during sluicing events. By monitorin
To measure a full range of accurate suspended-sediment data, multiple methods are being used at four sites along the Colorado River (see map and table). USGS technicians collect depth-integrated cross-section samples during regular quarterly visits and sluicing events. These samples provide the most accurate measure of suspended sediment in the water but can only be performed at a relatively infrequent interval. To collect additional data, automated pump samplers are programmed to collect samples between the visits by USGS technicians. In addition, three of these sites have continuous-suspended-sediment monitors installed to collect live data every 15 minutes. These monitors measure suspended-sediment concentration and turbidity using acoustic and optical backscatter. The combination of these methods allows for a larger range of grain sizes to be measured. The suspended-sediment concentration values from the continuous monitors will be calibrated to the suspended-sediment concentration values from the automated pump and depth integrated samples.
| Location | Automated Pump Sampler |
Quarterly Sample |
Sluice Sample |
Continuous Monitor |
|---|---|---|---|---|
| COLORADO RIVER BELOW IMPERIAL DAM, AZ-CA | Water Level Activated |
x | x | x |
| COLORADO RVR ABV DESILTING RTNS BLW IMPERIAL DAM | Water Level Activated |
x | x | |
| COLORADO RIVER ABOVE IMPERIAL DAM, AZ-CA | Set Interval | x | x | |
| COLORADO RIVER AT PICACHO STATE PARK, CA | Set Interval | x | x |
Like many other dams, Imperial Dam impounds much of the suspended sediment moving in the Colorado River but some of that suspended sediment makes its way to the All-American Canal, a major diversion for irrigation and municipal water. Water entering the All-American Canal is settled in several desilting basins to remove most of the remaining suspended sediment. The collected sediment from the desilting basins flows into the California Sluiceway and builds up until sluicing flows transport the sediment downstream into the Colorado River. At this time, the rate of sediment accumulation in the Sluiceway is not known. The timing of these sluicing events could be improved if sufficient suspended-sediment data was collected to determine this rate. Optimally scheduled sluicing events will ensure the most efficient use of Colorado River water to maintain the channel conditions of the California Sluiceway into the Colorado River.
The Imperial Dam Sediment project monitors the transport of suspended sediment from the All-American Canal desilting basins to the California Sluiceway below Imperial Dam and from the sluiceway downstream in the Colorado River during sluicing events. By monitorin
To measure a full range of accurate suspended-sediment data, multiple methods are being used at four sites along the Colorado River (see map and table). USGS technicians collect depth-integrated cross-section samples during regular quarterly visits and sluicing events. These samples provide the most accurate measure of suspended sediment in the water but can only be performed at a relatively infrequent interval. To collect additional data, automated pump samplers are programmed to collect samples between the visits by USGS technicians. In addition, three of these sites have continuous-suspended-sediment monitors installed to collect live data every 15 minutes. These monitors measure suspended-sediment concentration and turbidity using acoustic and optical backscatter. The combination of these methods allows for a larger range of grain sizes to be measured. The suspended-sediment concentration values from the continuous monitors will be calibrated to the suspended-sediment concentration values from the automated pump and depth integrated samples.
| Location | Automated Pump Sampler |
Quarterly Sample |
Sluice Sample |
Continuous Monitor |
|---|---|---|---|---|
| COLORADO RIVER BELOW IMPERIAL DAM, AZ-CA | Water Level Activated |
x | x | x |
| COLORADO RVR ABV DESILTING RTNS BLW IMPERIAL DAM | Water Level Activated |
x | x | |
| COLORADO RIVER ABOVE IMPERIAL DAM, AZ-CA | Set Interval | x | x | |
| COLORADO RIVER AT PICACHO STATE PARK, CA | Set Interval | x | x |