The following material was received by C. Newsom on March 19, 2001 from John Castles of the U. S. Army Corps of Engineers, as a replacement for Table C-2, Schedule A, B, and C. of the Regulation Schedule in the Regulation Plan for Coralville Lake.
|
Schedule A Normal Flood Control Operation Pool elevation at or forecast between 683 and 707 |
Conservation pool Schedule
Date Operation
15 Feb - 20 Mar 683 to 679^
20 Mar - 20 May Hold 679^
20 May - 15 Sep Hold 683
15 Sep - 15 Dec Hold 683-686*
15 Dec - 15 Feb Hold 683
Notes: ^ Variable draw down based on snow cover, ice, and 30 day climactic conditions coordinated with IDNR * Dates and elevation of fall pool raise coordinated with the IDNR |
| Condition | Operation |
|---|---|
| A-1 All Dates | Regulates pool level as nearly as possible
without adversely affecting downstream conditions. Do not release less than mimimum outflow of 150 cfs |
| A-2 15 December though 1 May | Maintain conservation pool according to schedule without exceeding release of 10,000cfs except as limited by conditions A-3, A-6 or A-7 |
| A-3 15 December through 1 May Stage at above or forecast to exceed... Lone Tree 16.0 feet Wapello 22.0 feet |
Reduce release to not less than 1,000 cfs to control flow to those discharges as near as possible during three days of crest at the respected station with due allowance to travel times. |
| A-4 1 May through 15 December | Maintain conservation pool according to schedule without exceeding release of 6,000cfs except as limited by conditions A-5, A-6 or A7 |
| A-5 1 May through 15 December Stage at above or forecast to exceed... Lone Tree 14.0 feet Wapello 21.0 feet |
Reduce release to not less than 1,000cfs to control flow to those discharges as near as possible during 3 days of crest at the respected station with due allowance to travel times. |
| A-6 All Dates Stage at above or forecast to exceed... Mississippi River at Burlington - 18.0 | Reduce release to 1,000cfs during seven days corresponding to the crest flow on the Mississippi River with due allowance for travel time. |
| A-7 Flash Flood: Any date flow at above or forecast to exceed 16,000cfs at Iowa City | Reduce release to not less than 1,000cfs to keep flow at or below 16,000cdf at Iowa City |
| Schedule B Major Flood Pool elevation at above or forecast to exceed 707 feet NGVD |
| Condition | Operation |
|---|---|
| B-1 Inflow has not Peaked |
Determine the pool elevation that would occur at the peak of the
inflow hydrograph. Release not more than allowed on table below:
15 Dec - 1 May 1 May - 15 Dec Elev. Outflow Elev. Outflow 707 10000 707 7000 708 10000 708 8000 709 10000 709 9000 710 10000 710 10000 711 11000 711 11000 711.1 12000 711.1 12000 711.2 13000 711.2 13000 711.3 14000 711.3 14000 711.4 15000 711.4 15000 711.5 16000 711.5 16000 711.6 17000 711.6 17000 711.7 18000 711.7 18000 711.8 19000 711.8 19000 711.9 20000 711.9 20000 712.0 and above - Gates Fully Open |
| B-2 Inflow has peaked |
Determine the minimum outflow required to utilize the
remaining storage below 712.0.
Release that flow or the present outflow - whichever is higher. |
| B-3 Reservoir Pool Falling |
Release outflow established by B-2 until elevation 707 is reached then gradually reduce flows to Schedule A |
| B-4 Emergency: flow forecast to exceed the control flow established by the U.S. Army Corps of Engineers for public exigency downstream. | Reduce release to keep flow at or below the control flow established by the "Corps". |
|
Schedule C Drought -- All Dates Any time pool below conservation according to Schedule A and inflow not sufficient to get to conservation pool. |
| Condition | Operation |
|---|---|
| C-1 Pool between Conservation and 678.0 feet |
Release 150 cfs |
| C-2 Pool between 677.0 and 678.0 |
Reduce release to 100 cfs |
| C-3 Pool below 677.0 feet |
Reduce release to 75 cfs |