4.1. INTRODUCTION TO ENHANCEMENT TECHNIQUES
Water quality enhancement opportunities can generally be in the watershed, in the reservoir,
and in the tailwater. To successfully identify an appropriate alternative, one must have a clear
understanding of the processes causing the water quality problem and the processes that will improve
or correct the problem. Hence, the previous chapters covering watershed, limnological, and
operational processes. In most situations, to improve or resolve a water quality problem, will require
the implementation of multiple alternatives, perhaps from all three areas of opportunity.
This chapter focuses on alternatives in these three areas. Watershed techniques are discussed
that are related to agricultural and livestock, farming, and forestry practices and other human activities.
In-reservoir techniques are presented to modify in-reservoir water quality or in-reservoir processes that
improve water quality in the reservoir and in the tailwater. Also discussed are in-structure techniques
that generally treat water during release to improve the quality downstream. Tailwater techniques are
discussed that improve quality after the water has been released. Other miscellaneous enhancement
opportunities are discussed.
The watershed techniques discussed include farming practices along streams, tillage versus no-
till farming, strip-cropping, pesticide/herbicide control, livestock waste control, forestry/logging
sedimentation control, and many other activities. In-reservoir enhancement techniques include selective
withdrawal and several operational derivatives, aeration/oxygenation, destratification and localized
mixing, and several operational modifications. In-structure techniques deal mostly with hydroturbine
releases and aeration or oxygenation of release water during passage through the turbine. Tailwater
techniques provisions for minimum flow and aerating weirs.