Chapter 15

freshwater must be free of: • dissolved salts • plant and animal waste • bacterial contamination

97.57%

3%; not much available • ice and glaciers = 78% • groundwater = 21% • rivers, lakes, and soils = 1%

• antiquated water delivery systems: aging pipes = leaks/water loss • depletion of resources • mismanagement (bad distribution) • industrial needs • water conflicts/wars • increasing human population

• evaporation: moves water to atmosphere • evapotranspiration: moves water to atmosphere • cloud formation • precipitation • groundwater, oceans, bodies of water

underground water resources -porous rock that becomes saturated with water

closer to surface -top layer = more porous rock, recharged through rainfall

• has layer of impermeable rock - recharged in one location

• toilets = 25% • lawns, etc = 25% • drinking/cooking = 2%

ground and surface water used for irrigation of agricultural crops

• surface or flood irrigation: simple, but wasteful • spray: continually pumps water; simple, but wasteful • trickle: water directed at roots; work-intensive; expensive; efficient • subirrigation: dig pipes in ground directed at roots; work-intensive; expensive; efficient

• most used for cooling (most is returned to source) - some used for waste disposal

• does not remove water - used for hydroelectric power, recreation, and navigation

addition of substances or energy to water which changes natural ecosystems or interferes with water use

• toxic chemicals (bioaccumulation and biomagnification) • dissolved organic matter • disease-causing organisms • nutrients • particles

pollutants that can be traced to a single source

pollutants that do not come from a defined source

• sets water quality standards for surface water - limits effluent discharges into water

• decomposition of organic matter results in increased oxygen consumption • pollution of water with organic matter or nutrients (resulting in algal growth) leads to increased biological oxygen demand (BOD) • decreasing oxygen concentration impacts other aquatic organisms

• municipal water pollution • agricultural water pollution • industrial water pollution • thermal water pollution • marine oil pollution • groundwater pollution

• stormwater runoff • wastes from industries • homes and commercial establishments • fecal coliform bacteria • pharmaceutical residues

• fertilizer and pesticide use • soil erosion • runoff from animal feedlots

• disposal of wastes 2. mining activities

• water is used for cooling and is returned to its source at higher temps • changes in water temp can impact organisms and decrease dissolved oxygen content