The High Rock "Interactive Rule Curve"

Current High Rock Lake Conditions
High Rock Lake Level
5.01
Feet Below Full
Estimated Total Inflow
1815
Cubic Feet Per Second
Appropriate "Rule Curve" rule: 8 **
Rule 8 Range
3.66 to 26.00
Feet Below Full
MAX. Weekly Generation
5410
MegaWatt Hours
MAX. Average Discharge
1610
Cubic Feet Per Second
If the MAX. allowed generation under rule 8 were produced, High Rock Lake would rise:
0.43
Inches Per Day
3.04
Inches Per Week
Rules that could be appropriate today

1

2

3

8

0.00 ft. to -2.00 ft.

-2.00 ft. to -2.80 ft.

-2.80 ft. to -3.66 ft.

-3.66 ft. to -26.00 ft.

 

** The Rule Curve included in the current license for Project 2197 is not intended as a DAILY operating guide. It is used only as a guide for planning the next weeks allowable generation. Rule 8 is currently the only rule that attempts to protect the lake levels in High Rock Lake. Every other rule allows generation in amounts FAR greater than is possible with the amount of water normally flowing down the Yadkin River.

 

 

 

The High Rock operating guide is presented in Figure 2.7-1. It should be noted that this figure presents reservoir elevation in terms of drawdown (in feet, right vertical axis) and depletion (in day-second-feet, left vertical axis). The High Rock operating guide regulates energy generation, not headwater. The following "rules" are applied to the guide to determine generation values:

 

Rule 1: If the elevation of High Rock Reservoir is greater than that indicated by Line 1 or if, during the next calendar week, the elevation of High Rock Reservoir is expected to be greater than indicated by Line 1, generate 32,088 MWh, maximum, (191,000 kW average) each week unless spill is anticipated. If spill is anticipated, generation should be at maximum practicable rate.

 

Rule 2: If the elevation of High Rock Reservoir is greater than that indicated by Line 2, but less than that indicated by Line 1, generate 27,313 MWh maximum, (162.6 MW average), each week.

 

Rule 3: If the elevation of High Rock Reservoir is greater than that indicated by Line 3, but less than that indicated by Line 2, generate 21,583 MWh maximum, (128.5 MW average), each week.

 

Rule 4: If the elevation of High Rock Reservoir is greater than that indicated by line 4, but less than that indicated by Line 3, generate 16,044 MWh maximum, (95.5 MW average), each week.

 

Rule 5: If the elevation of High Rock Reservoir is greater than that indicated by Line 5, but less than that indicated by Line 4, generate 11,084 MWh maximum, (66.0 MW average), each week.

 

Rule 6: If the elevation at High Rock Reservoir is greater than that indicated by line 6, but less than that indicated by Line 5, generate 8,522 MWh maximum, (50.7 MW average), each week.

 

Rule 7: If the elevation of High Rock Reservoir is greater than 623.9 feet, but less than that indicated by Line 6, generate approximately 6,000 MWh each week to sustain a minimum release of 1800 cfs (35.7 MW) average weekly.

 

Rule 8

a) March 6 through May 13: If the elevation of High Rock Reservoir is less than that indicated by Line 7, limit the discharge through High Rock turbines to 1500 cfs, average for the period.

 

b) May 14 through July 29: If the elevation of High Rock Reservoir is less than that indicated by Line 7, limit the discharge though High Rock turbines to 1610 cfs, average for the period.

 

c) July 30 through September 15: If the elevation of High Rock Reservoir is less than that indicated by Line 7, limit the discharge through High Rock turbines to 1400 cfs, average for the period.

Note: In the event of conflict between Rule 8 and the other rules, Rule 8 will take precedence.