Chapter 9 Water Resources

What are the benefits and drawbacks of different methods of irrigation?

Aquifers can be depleted if overused; waterlogging can occur; flood irrigation has high evaporation losses; drip irrigation is most efficient but expensive.

What is the largest human use of freshwater?

Irrigation accounts for 70% of the world's freshwater use.

What are impervious surfaces, and how do they affect the environment?

Human-made structures that don't allow water to reach the soil, leading to reduced groundwater recharge and increased flood risk.

What are the types of irrigation?

Drip irrigation, flood irrigation, furrow irrigation, and spray irrigation.

What is an unconfined aquifer?

An aquifer made of porous rock covered by soil, allowing water to flow easily in and out.

What is a confined aquifer?

An aquifer surrounded by impermeable rock or clay that impedes water flow into and out of the aquifer.

How does groundwater recharge occur?

Groundwater recharge occurs when precipitation percolates through the soil into an aquifer.

What is saltwater intrusion?

The movement of saltwater into freshwater aquifers, often caused by groundwater depletion near oceans.

What are the negative effects of urbanization on the hydrologic cycle?

Depletion of resources and saltwater intrusion, along with decreased carbon dioxide due to fossil fuel use.

How can water infiltration in urban areas be increased?

By reducing impervious surfaces, using permeable pavement, and increasing vegetation.

What is the efficiency of drip irrigation compared to other methods?

Drip irrigation is over 95% efficient, making it the most efficient method.

What impact does drought have on water resources?

Leads to water shortages, reduced plant growth, decreased recharge, and increased fire risk.

What challenges are associated with desalinization?

It is energy intensive, and managing its waste products is challenging.

What percentage of the world's freshwater is used for agriculture?

Approximately 70%.

What is hydroponic agriculture and its benefits?

A cultivation method using nutrient-rich solutions; it uses up to 95% less water than traditional irrigation.

What is the impact of waterlogging?

It can raise the groundwater table and inhibit plants' ability to absorb oxygen.

Why is spray irrigation considered more efficient than flood irrigation?

Because it results in less water loss to evaporation and runoff.

What percentage of the world’s freshwater is used for industrial purposes?

Roughly 20%.

What is the role of groundwater recharge areas?

They allow water to percolate into confined aquifers.

What proportion of the world's freshwater is used for domestic purposes?

Approximately 10%.