Case Study: Land subsistence in the American Southwest

Land subsidence is the lowering of the land-surface elevation from changes that take place underground. Human activity pumping water, oil, and gas from underground reservoirs; dissolution of limestone aquifers (sinkholes); collapse of underground mines; drainage of organic soils; and initial wetting of dry soils (hydrocompaction) are all common causes of land subsidence. Overdrafting of aquifers is the major cause of subsidence in the southwestern United States. As ground water pumping increases, land subsidence increases as well. In many aquifers, ground water is pumped from pore spaces between grains of sand and gravel. If an aquifer has beds of clay or silt within or next to it, the lowered water pressure in the sand and gravel causes slow drainage of water from the clay  and silt beds. Land subsidence has been getting worse over the passed few years because large amount of ground water has been excessively withdrawn from aquifers. Reduced water pressure is a loss of support for the clay and silt beds, since these beds are compressible they compact and it results with a lowering of the land surface.

Land subsidence has many impacts including changes in elevation and slope of streams, canals, and drains; damage to bridges, roads, railroads, storm drains, sanitary sewers, canals, and levees; damage to private and public buildings; and failure of well casings from forces generated by compaction of fine-grained materials in aquifer systems. Subsidence has resulted in tides moving into low-lying areas that were previously above high-tide levels, in some coastal areas.

In some areas where ground water pumping has causes subsidence, switching from ground water to surface water supplies has stopped the subsidence. If surface water is not available, then other means must be taken to reduce subsidence. Possibilities include reducing water use and determining locations for pumping and artificial recharge that will minimize subsidence. 

Water Use in Agriculture

Drip irrigation is the most common type of “micro-irrigation”. This method includes water running through small horizontal pipes (with holes in them) either buried or lying slightly above the ground next to the crops that slowly drip water onto the crops roots and stems.

            Pros:

·      Is low pressure, low volume irrigation system suitable for high-return value crops such as fruits and vegetable crops.

·      Can increase yields and decrease water, fertilizer and labor requirements.

·      Applies water only to the plants root zone, saving water because of the high application efficiency and high water distribution

·      Any water-soluble fertilizer may be injected through a micro-irrigation system.

           

            Cons:

·      Costly investment

·      Requires frequent maintenance

·      Requires constant monitoring

Sprinkler Irrigation is a method of applying irrigation water, which is similar to rainfall. Water is distributed through a system of pipes usually by pumping. It is then sprayed into the air and irrigated entire soil surface through spray heads so that it breaks up into small water drops, which fall to the ground.

            Pros:

·      Low pressure to save energy

·      Achieves high uniformity of application

·      Water irrigated efficiently if combined with a scheduling system

·      Easy to apply

·      Fixed systems are cheaper to manage

            Cons:

·      Higher capital costs

·      Needs care in windy conditions so uniformity isn’t distorted

Surface irrigation is one of the oldest methods, where farmers flow water down small trenches running through their crops.

            Pros:

·      Cheap / low-tech method

·      Less water is lost to evaporation

·      Less affected by climate and water factors

·      Easy to see effectiveness

            Cons:

·      More water can be lost from runoff at the edges of the fields

·      More labor required

·      Drainage could be an issue

·      May be a higher disease pressure

My Opinion:

I would say sprinkler irrigation is the best of the three for farmers use. I chose this method because it has the most pros and the least cons, so it would be the best choice in my opinion. Sprinkler irrigation has low pressure to save energy, achieves high uniformity of application, is a scheduled system, is easy to apply and is cheap to manage. The main downside of this method is that it is costly however the efficiency is great; therefore sprinkler irrigation would be the best of the three methods.

Rhine River Case Study

The River Rhine rises in the Swiss Alps about 3,353 meters above sea level and flows north, passing through or bordering Switzerland, Liechtenstein, Australia, Germany, France, and the Netherlands.  The factors that make the Rhine River the “Industrial Heartland” include that it encompassed the major empires, enabled trade and economic growth, linked European countries together and it is the most efficient way to transport people and goods. The physical body of water also enabled industrialization to occur more effectively.

The industrial heartland of North America is the Rust Belt; it is the region straddling the upper Northeastern United States, the Great Lakes, and the Midwest States. It is surrounded by water causing it to be a suitable area for trade and for the growth of the economy.  The Great Lakes and nearby Appalachia were utilized for transportation and natural resources. This enabled thriving coal and steel industries.

There are many impacts that human activity has had on the Rhine River basin. Farmland or buildings have replaced the Rhine’s riverside marsh and floodplain, which was used to hold back floodwater. Improved flood protection measures upstream cause the floodwater to move downstream more quickly than it used to. The river has been involved in a straightening process due to improved navigation for shipping; meaning the distance has been reduced, so this means that water moves downstream more quickly. Urbanization in the Rhine catchment area has also helped flooding due to the fact that the concrete and tarmac send more water to the river than the fields they replaced. The upper Rhine is used for generating hydroelectric power. These are all human causes on the Rhine River.

Reincorporating vegetation into the surrounding areas of the river where meadows and fields used to be would be an aiding solution to the flooding issue of Rhine River. It would act as an infiltration system and absorb excess waters, however it would be difficult to implement by people as times are getting more industrialized and advanced and more natural land is being replaced by buildings instead of the other way around. Reinforcing earth dykes with steel piling with stone blocks to reduce erosion is another solution that could be difficulty implementing as it would be costly, tedious and time consuming enhancing every dyke with steel however it would be worth it in the long run. Limiting residential development in areas where flood risks are likely is another solution to prolonging the longevity of people in this country however the houses in this area are most likely cheaper and more affordable for families that cannot support the expenses of another house therefore stopping people from living in these areas could end up putting people on the streets and killing them anyway. Allowing the river to flow back through marshland areas which had been previously been sealed off for navigation purposes would create a much further journey for the river to flow, lessening the intensity and speed of flooding however it would be inconvenient for travelers and shipping purposes as the journey would be much longer than if the river took a shorter route.

Aquaculture

Define Aquaculture: 

Aquaculture is also known as fish or shellfish farming. It refers to the breeding, rearing and harvesting of plants and animals in all types of water environment including ponds, rivers, lakes and oceans. Aquaculture produces food fish, sport fish, bait fish, ornamental fish, crustaceans, mollusks, algae, sea vegetables and fish eggs.

Looking at social (on people), environmental, and economic pros and cons of aquaculture.

Social

            Pros:

·      Creates jobs in the community

·      Helps feed growing world population

·      Meets increasing consumer demand for seafood

            Cons:

·      May conflict with other users of water bodies such as lobstermen, fishermen or migrating fish

·      May threaten livelihood of fishermen

·      May have an impact on consumers health because of chemicals found in fish that come from fish farms

Environmental

            Pros:

·      Places more emphasis on protecting coastal waters from pollution, especially in the case of mollusk and seaweed culture

·      Fish farms can me made anywhere on the environment such as coastal areas, inland lakes, and rivers.

·      It is the fastest growing method of food production

            Cons:

·      Can pollute water systems with excess nutrients such as fish feed and wastes, chemicals and antibiotics

·      Can compromise the aesthetic beauty of coastlines

·      Issue with water contamination

Economic

            Pros:

·      Increases revenue on the city, state, and national level

·      Reduces seafood trade deficit

·      Encourages local investments

            Cons:

·      Can be an unpredictable enterprise for small local communities due to its susceptibility to severe weather, predators, disease, and global competition.

·      Causes a decrease in supply and demand depending on the limited amount of healthy fish or varying consumer demands

·      Requires a lot of funding

My point of view on aquaculture:

Considering the pros and cons of aquaculture, I would say it is a bad thing because of the negative impacts it brings. Aquaculture has impacts socially, environmentally and economically.  Socially, it has an impact on consumer’s health because of chemicals found in fish that come from fish farms. Environmentally, it pollutes water systems with excess nutrients (fish feed & wastes), chemicals and antibiotics. Economically, it is an unpredictable enterprise for small local communities due to its susceptibility to severe weather, predators, disease and global competition. Overall looking at the impacts it has in the different ways, it concludes to impact humans negatively in many ways. In my opinion aquaculture is not a good thing, mainly because of the fact that it puts a risks human health.