rule curves
Rule curves for the eight lakes in the Oswego River Basin:
Does the Canal Corporation try to minimize flood damage?
Lake-level regulation efforts are aimed at minimizing flood
damage within the entire Oswego River Basin. Typically, following
the navigation season, the system's water levels are lowered to
provide storage for spring snowmelt and storm runoff. Prior to
navigation season, water levels are raised gradually to
predetermined safe levels for summer use. In the summer, levels are
regulated to provide reserve capacity sufficient to contain moderate
runoff. Seasonal lake levels and other important factors such as
maximum and minimum navigation levels are indicated on graphs called
"rule curves" that depict ideal levels for each lake.
High Water Levels |
Flood |
|
Water Supply for all uses
Drinking water
Sewage plants
Critical Habitat
Navigation
Irrigation |
|
· |
Low Water Levels |
Flood Mitigation |
| No Water |
No Drinking Water
No Navigation
Severe Damage to Critical Habitat |
Rule curves are the historical compromise for water level
management that have been established to balance competing interests
for target water levels. The rule curve process starts by
establishing the top and bottom of the curves (highest tolerable
level, lowest tolerable level) to avoid at all costs severe flooding
or severe drought conditions. Within that range, navigation levels
and municipal water supply are given the highest priorities to
ensure a stable, reliable water supply throughout low water summer
months. Critical habitat concerns also drive target levels toward
the high side of the range to ensure against damage to delicate
natural resources.
In order to avoid floods, demand for high levels must be balanced
against the effects on property owners. Typically, floods are
brought on by:
- Rapid spring snowmelt/runoff
- Heavy spring rains/heavy runoff
- Heavy fall rains before the winter freeze.
To deal with these acts of nature, water levels are
raised/lowered within tolerable limits by season.
- FALL – At the close of the navigation season, water levels
are drawn down for storage capacity anticipating spring runoff.
- WINTER – The lowest water level on the system can be
achieved mindful of water supply needs.
- SPRING – Storage capacity is maintained as long as possible
to accept heavy runoffs, but gradual system increases must be
undertaken to ensure target levels are reached for summer low
water condition needs.
- SUMMER – Competing needs must be balanced with the available
water supply.
For additional information on water management of the NYS Canal
System contact: Syracuse Division Canal Office, Water Management
(315) 437-2741.
What agencies provide flood and flood plain
management assistance?
The NYS Department of
Environmental Conservation (DEC) works with the State
Emergency Management Office (SEMO) to help communities plan for
flood disaster.
DEC is New York State’s flood plain management agency, which
provides technical assistance to the state’s 1,500 flood-prone
communities to help them prevent loss of life and to mitigate flood
damages. DEC and SEMO work together to train community response
teams by providing instructional materials, tests and drills, and
evaluation of local training programs. Fire, police and sheriff's
departments, and volunteer or professional emergency squads benefit
from flood preparedness training.
DEC and SEMO also provide planning guides and resource
information. They help local officials develop or improve flood
preparedness plans and coordinate their plans with regional, state
and federal agencies. DEC is New York's coordinating agency for the Federal
Emergency Management Agency (FEMA), which administers the
National Flood Insurance Program. DEC helps communities understand
and administer this program’s regulations.
For additional information contact NYSDEC Flood Protection Bureau
at (518) 457-3157.
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