A water level control and energy recovery system for a canal having at least one lock (4.1,4.3), the system comprising: an upstream conduit arranged to be fluidly coupled to water upstream of a canal lock upper gate; a downstream conduit arranged to be fluidly coupled to water downstream of a canal lock lower gate; an energy generating arrangement (5.4, 7.3, 14.7, 15.7, 16.6) positioned in a flow conduit between the upstream conduit and the downstream conduit arranged to generate energy from flow of water through the upstream conduit to the downstream conduit; a control arrangement (17.5) arranged to obtain at least one lock state input related to the state or intended state of the canal lock and to provide a flow control output for controlling the flow through the flow conduit, wherein the control arrangement is further arranged to obtain a canal state indication indicative of available water upstream of the lock and wherein the control arrangement is arranged to produce a flow control output which varies with both the lock state inputs and the canal state indication to implement a flow control strategy for the canal responsive to the available water upstream, wherein the canal state indication is derived from a measure of water level in at least one remote water source feeding the canal upstream of the lock, and further comprising at least one of the following: a) wherein the canal state indication is derived from at least one predictive water availability parameter indicating likely future state of the canal, b) wherein the control arrangement is arranged to receive at least one further input indicative of a measure of current or predicted energy demand and to adjust the flow in dependence of said current or predicted energy demand. an upstream conduit arranged to be fluidly coupled to water upstream of a canal lock upper gate; a downstream conduit arranged to be fluidly coupled to water downstream of a canal lock lower gate; an energy generating arrangement (5.4, 7.3, 14.7, 15.7, 16.6) positioned in a flow conduit between the upstream conduit and the downstream conduit arranged to generate energy from flow of water through the upstream conduit to the downstream conduit; a control arrangement (17.5) arranged to obtain at least one lock state input related to the state or intended state of the canal lock and to provide a flow control output for controlling the flow through the flow conduit, wherein the control arrangement is further arranged to obtain a canal state indication indicative of available water upstream of the lock and wherein the control arrangement is arranged to produce a flow control output which varies with both the lock state inputs and the canal state indication to implement a flow control strategy for the canal responsive to the available water upstream, wherein the canal state indication is derived from a measure of water level in at least one remote water source feeding the canal upstream of the lock, and further comprising at least one of the following: a) wherein the canal state indication is derived from at least one predictive water availability parameter indicating likely future state of the canal, b) wherein the control arrangement is arranged to receive at least one further input indicative of a measure of current or predicted energy demand and to adjust the flow in dependence of said current or predicted energy demand. a) wherein the canal state indication is derived from at least one predictive water availability parameter indicating likely future state of the canal, b) wherein the control arrangement is arranged to receive at least one further input indicative of a measure of current or predicted energy demand and to adjust the flow in dependence of said current or predicted energy demand.