Land and Watershed Management - Practices of Irrigation and On-farm Water Management - page 228

important but also more difficult. Land and water management is especially criti-
cal as the use of upstream watersheds can drastically affect large numbers of people
living in downstream watersheds.
It is necessary to identify and address land-use practices and other human
activities

that pollute local water resources or otherwise alter watershed

functions.

Box 6.1 Watershed Pollution and Control-Sample Lesson
from Ohio

Since passage of the federal Clean Water Act in 1972 and the Safe Drinking
Water Act in 1974, great progress has been made in reducing the amount of
pollutants discharged into Ohio's waters from point sources such as wastew-
ater treatment plants and industries. But as point sources of pollution were
reduced, other forms of pollution, called nonpoint source or diffuse pollu-
tion, came to the forefront. Nonpoint source pollution results from human
land-use practices such as agriculture, mining, forestry, home septic sys-
tems, and contaminated runoff from urban landscapes. Now these nonpoint
sources of pollution, combined with the physical destruction of aquatic
habitat, are the major remaining sources of impairment of Ohio's rivers
and lakes.

6.6.2 Components of Watershed Management

Watershed management consists of those coordinated human activities which aimed
at controlling, enhancing, or restoring watershed functions. Among various areas
of watershed management are improved land management, water harvesting and
storage structures, improved agricultural equipments, integrated nutrient manage-
ment, vermi-composting, nuclear polyhedrosis virus (NPV) production, improved
cropping systems, and soil conservation measures.
Each state is required to develop the limit for the maximum amount of a
specific pollutant (tolerable limit) that a water body can accommodate without
causing the water body to become unable to serve its beneficial use (MDL), for
all water bodies listed “impared.” The MDL process is just one component of
watershed management. Effective watershed management is an ongoing process
that must be flexible enough to adapt to the unique characteristics of differ-
ent watersheds as well as changing circumstances within a single watershed. It
results in reduction of contaminants within watersheds and improvement of water
quality.