Developing a Lock Operation Strategy for Pool
Lowering
Richard L. Stockstill1
Abstract
modeling system determined the
lock was completed in 1930. A
optimum valve operations to obtain
second lock, landward from the first,
The pool lowering capability of
steady-state conditions and provided
was completed in 1932. The lock
Locks and Dam 1, Mississippi River,
the head-discharge relationship for
chamber is 17.1 m wide by 121.9 m
can be increased if the lock filling
the lock.
long and has a design lift of 11.6 m.
and emptying system is used as a
Rehabilitation of the landward lock,
discharge outlet. However, the
the subject of this study, was com-
Introduction
steady-state conditions of passing
pleted in 1981. Details of the filling
flow through the lock system and the
and emptying system are provided
conditions during the acceleration to
A valve operation scheme is
on the plan and elevation drawing of
steady state can include excessively
developed for passing flow through
Figure 1. The need to provide a
low pressures downstream of the fill-
the filling and emptying system of
means of pool lowering has led to
ing and emptying valves. A lock
Lock 1, Mississippi River. The Locks
the idea of using the lock culvert
valve operation scheme that pro-
and Dam 1 project is located at Mis-
system as a pool outflow structure.
vided acceptable flow conditions in
sissippi River mile 847.6 above the
The questions to be answered are
the lock system was developed
mouth of the Ohio River between
what is the best manner in which to
using a numerical flow model of the
the cities of St. Paul and Minneapo-
operate the valve and what is the
lock filling and emptying systems
lis, MN. The original lock and dam
head-discharge relationship for the
coupled with commercial optimiza-
was opened to navigation in 1917.
lock system.
tion software. The flow model was
The dam is a 175-m overflow struc-
The purpose of this study is to
validated with field data obtained at
ture having a privately owned hydro
develop a lock operation scheme for
the Lock 1 prototype. The resulting
power station. Construction of a new
Figure 1. Plan and profile of landward lock, Lock and Dam 1, Mississippi River
1
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