Essay on Distribution and Use of Water

70 percent of the earths surface is covered with water. Ocean water forms 97% of available water while fresh water is only 3%. Ice takes up 2.1% out of the 3% and thus, the main source of accessible fresh water is groundwater which is only 0.61%. Other sources include surface water, soil moisture, and the atmosphere.

Use of water depends on the availability as well as socioeconomic activities. In the US, 57% of water is used for industrial purposes, 34% for Agriculture and 9% for municipal use. The units of measurement of water include gallons liters and cubic feet which are all inter-convertible.

Water is termed as the vital molecule because our bodies are 65% water and the brain is 95% water. The chemical formula for water is H2O which means that two hydrogen atoms are joined to an Oxygen atom by covalent bonds. The hydrogen side remains with a positive charge while the oxygen side develops a negative charge. The molecules are then joined using hydrogen bonds resulting from the polarities created. The hydrogen bonds make water to possess unique properties including:

High melting and boiling points

High heat of vaporization

High specific heat

Anomalous expansion of water, i.e., water expands while freezing.

High surface tension

Excellent solvent for salt and polar molecules

Ability to absorb infrared radiation

California Precipitation patterns

Water problems in California are caused by:

Uneven distribution of precipitation for various regions as well as different times of the year,

Complicated legal and political frameworks controlling water resources

Precipitation patterns in California based on regions are as follows:

Highest precipitation in the Sierra Nevada and northern coast

More precipitation on the coast than inland

More precipitation in the north than south

Very low precipitation in the valleys, especially east of the Sierra Nevada

From the above, we can note that precipitation patterns present problems due to the reasons below:

Precipitation falls in the wrong places, mountains, and Northern California, where few people live, and not in the valleys and in Southern California where most people live.

Precipitation falls at the wrong time, in the winter and not in the summer where water use is highest.

Precipitation varies from year to year, and often a large amount of rain falls in a very short time.

The concept of precipitation can be explained based on relative humidity. This is because precipitation will occur when warm air with a lot of moisture cools, and this requires a process that can lift the warm moist air to higher altitudes.

Average precipitation in California is 193 million acre-feet per year. 121 million acre-feet are lost to evaporation, infiltration, and transpiration by plants. The remaining 72 million acre-feet end up as runoff, most of it in the Sacramento River.

The Hydrologic Cycle

This refers to the theoretical model of how water moves through the environment. The cycle has the steps of evaporation, condensation, precipitation, Infiltration, Runoff, and evapotranspiration.

Evaporation refers to the process in which water vapor is released into the atmosphere as a result of high heat energy to match the latent heat of vaporization. Condensation occurs when moist air is cooled to reach 100% relative humidity when the water vapor forms small droplets from the water vapor. Precipitation is any water that falls on the ground (snow, rain, and hail). Infiltration refers to the process where the precipitated water percolates into the earth. Runoff refers to water draining downhill as a result of hard rains or impermeability of the earth surface. Runoff eventually collects in streams, rivers, and lakes. Evapotranspiration refers to the combined process of evaporation from water bodies and transpiration by plants.

Watersheds refer to surface water basins such as rivers and lakes. Groundwater basins, on the other hand, are located deep in the earth below the surface. The Hydrologic Equation is a mass-balance equation that allows hydrologist to keep track of water in a basin, surface water body, or groundwater reservoir.

Surface Water Hydrology Runoff and Hydrographs

Factors affecting runoff include:

Topography Flow starts sooner on a steeper terrain

Elevations Higher elevations have lower temperatures and thus less evaporation and more precipitation

Vegetation Intercepts rainfall, reducing and moderating runoff

Soil type and geology Affects infiltration rates

Human modifications of land surfaces

A hydrograph is a graphical representation of the flow in a river or creek versus time. It can be used to estimate flooding risk and thus for planning by hydrologists, civil engineers, and land use planners.

Groundwater

This is the largest reservoir of easily accessible freshwater. Groundwater occurs in small open spaces underground. Californias aquifers contain about 850 million acre-feet of water, about 20 times as much as can be stored behind all of the states hundreds of dams. An aquifer is defined as a geologic unit that can store and transmit water fast enough to supply reasonable amounts of water to wells. Aquifers are either confined or unconfined depending on whether they are open to recharge from the land surface.

Amount of water present underground depends on the porosity of the material while permeability (Hydraulic conductivity) describes how well a geologic material can transmit water.

Other key terms include:

Porosity (n) total open pore space

Effective Porosity (one) connected open pore space

Specific retention (Sr) percentage of water that is held by porous medium when drained by gravity

Specific yield (Sy) percentage of open pore space that can be drained by gravity Hydraulic conductivity (K) controls the rate of fluid flow

Storativity (S) amount of water released from, or taken up into storage per unit change of hydraulic head (see definition of hydraulic head below)

Groundwater in the San Joaquin Valley and Water Quality

Groundwater table elevations and flow directions in the San Joaquin valley indicate that the water table is highest at the end and sides of the valley. The water originates in the mountains surrounding the valley with their high precipitation and then moves into the valley via rivers or underground as groundwater. Groundwater then discharges into rivers at the lowest points of the valley. Water leaves the valley through rivers flowing into the delta and through evaporation into the atmosphere.

Total Dissolved Solids is a water quality indicator. Standards have been set up to identify safe drinking water based on maximum contaminant level.

Groundwater contamination

Contaminants include:

Inorganic contaminants such as arsenic and lead

Petroleum-based organic chemicals

Chlorinated organic chemicals

Groundwater clean-up technologies include:

Natural attenuation involves leaving contaminants to break down over time

Pump and treat

Vapor extraction

Air Sparging

Permeable reactive barriers

Californias Pristine Waterscape and Current Waterscape

The original waterscape of California has changed over the years due to the human activities. For instance, thousands of dams have been built across the two main rivers: Sacramento River and the San Joaquin River.

As for the Buena Vista and the Kern lakes, they are surrounded by swamplands. These came up as a result of sedimentation of silt by the Kern River which has changed its course severally over the past years.