Evaluating policy options for integrated and cost effective river management in the tidal Ouse

The River Ouse forms a significant part of the Humber river system, which
drains about one fifth of the land area of England and provides the largest fresh
water input to the North Sea from the UK. The tidal Ouse has suffered from a sag
of dissolved oxygen (DO) during the last few decades, caused by effluent
discharges from industries and Sewage Treatment Works (STWs). Poor water
quality during the summer prevents the return of salmon, which is regarded by the
Environment Agency (EA) as a key indicator of rivers' ecological health. The EA
proposed to increase water quality in the Ouse by implementing more stringent
environmental policies. This conventional management option, however, usually
offers less flexibility in compliance and incurs excessive costs of pollution
abatement to industries and STWs.
This thesis explores the potential to improve water management by adopting an
integrated and cost effective river policy, which allows for variation in the
assimilative capacity of river water. Various options to improve water quality are
considered in a comprehensive framework for river policy. Reduction in both
effluent discharges and water abstraction are considered together with choice of
location for effluent discharge. Different instruments of environmental policy,
tax-subsidy scheme (TSS) and tradable pollution permits (TPP) systems are
compared with the command and control (CAC) approach. A hydrological model
from the EA is combined with an economic model to identify the least cost
solution for water quality management in the river system. This thesis provides a
theoretical discussion of this problem in both static and dynamic settings. This
framework is then applied to the empirical case of the tidal Ouse for particular
water quality targets. To achieve the water quality target at least cost is a
constrained optimisation problem, solved by computing software. The integrated
river policy is able to achieve a significant improvement in water quality at lower
cost than is currently incurred. This thesis also compares the different policy
instruments for delivering this water quality improvement in the tidal Ouse.