The Canal that Accidentally Grew a Forest in the Arizona Desert

Summary

This video explores the Central Arizona Project Canal, a vital water infrastructure that brings 500 billion gallons of water yearly from the Colorado River to Arizona's population. It highlights how this canal, completed in 1993, supports cities like Phoenix and Tucson, enabling lush landscapes and agriculture in the desert. Interestingly, the canal also acts as an inadvertent water-harvesting structure, creating native forests and diverse ecosystems along its path. This video delves into how human-made systems can unexpectedly foster ecological benefits in desert landscapes, showcasing both the challenges and surprising solutions in water management.

Takeaways

• 😀 The Central Arizona Project canal brings 500 billion gallons of water from the Colorado River to the Phoenix Basin each year, serving 80% of Arizona's population.
• 😀 The Colorado River used to flow all the way to the ocean through Mexico, but now it doesn't make it to the ocean due to excessive water extraction.
• 😀 The canal travels 336 miles and was completed in 1993, with construction starting in 1973, coinciding with the narrator's birth year.
• 😀 Every year, about 5 million gallons of water evaporate from the canal, while Lake Pleasant nearby loses about 16 million gallons to evaporation.
• 😀 Over 100 billion gallons of water from the canal are pumped back into the ground annually, replenishing the aquifer for future use.
• 😀 Arizona's green lawns, golf courses, agriculture, and urban sprawl are made possible due to the redirection of Colorado River water through the canal.
• 😀 The canal functions unintentionally as a water harvesting structure, collecting runoff water from monsoon rains and flash floods.
• 😀 The canal's berm acts as a giant swale, capturing flowing water and creating a native forest along its path due to the accumulated moisture.
• 😀 Bill Mollison, a permaculture expert, visited the Sonoran Desert in the 1980s to demonstrate how swales can create forests, and this concept is visible today along the canal.
• 😀 The canal's infrastructure, while not biologically designed, has inadvertently led to the growth of diverse ecosystems and habitats in the desert.
• 😀 The area around the canal, especially the mesquite tree forest, creates a microclimate that provides shade, moisture, and fertility, enhancing local ecology.

Q & A

What is the Central Arizona Project Canal and why is it important?

The Central Arizona Project Canal is a large water transportation system that brings 500 billion gallons of water every year from the Colorado River to the Phoenix Basin. It is crucial because it provides water to 80% of Arizona's population, including urban areas like Phoenix and Tucson, enabling agriculture, urban development, and green spaces in the desert region.

Why doesn't the Colorado River reach the ocean anymore?

The Colorado River no longer reaches the ocean because so much water is extracted by the states that use it, including Arizona. This redirection of water has significantly reduced the river's flow to Mexico and the Gulf of California.

How long is the Central Arizona Project Canal and what challenges did it face during construction?

The canal spans 336 miles and required significant engineering efforts to pump water over mountain ranges, as it relies on gravity to move water. The construction of the canal started in 1973 and was completed in 1993, taking about 20 years.

What happens to the water transported by the Central Arizona Project Canal?

About 5 million gallons of water evaporate each year from the canal, and some water is pumped into Lake Pleasant where 16 million gallons evaporate annually. Additionally, over 100 billion gallons are pumped back into the ground to replenish underground aquifers for future use.

How does the Central Arizona Project Canal impact the landscape?

The canal serves as a massive water-harvesting structure in the desert. Its elevated position prevents runoff from washing into the canal, while the surrounding land collects water and supports native vegetation, inadvertently creating ecosystems that mimic water harvesting techniques in permaculture.

What is the connection between the canal and permaculture principles?

The canal unintentionally follows permaculture principles by creating a swale-like feature in the landscape. It intercepts water runoff, creating a microclimate where trees and vegetation can grow, much like swales designed in permaculture to capture rainwater and support plant growth.

How does the Central Arizona Project Canal contribute to the local ecology?

While the canal itself is a human-made structure primarily for water delivery, it inadvertently supports local ecology by providing water and creating microclimates that sustain native forests and a diversity of plant species, particularly during monsoon rains.

What role does Lake Pleasant play in the water management system?

Lake Pleasant acts as a reservoir where water from the canal is pumped to be stored, but a significant amount of water also evaporates from the lake each year. This evaporation helps manage the water balance and contributes to the local water supply system.

How do native forests and vegetation thrive along the canal?

The canal's elevated structure traps water from monsoon rains, which flows into washes and accumulates on the canal's uphill side. This leads to the formation of native forests and a diversity of vegetation, which benefits the local ecosystem by creating shaded, fertile areas in an otherwise arid desert.

What is the significance of the native mesquite trees mentioned in the script?

The native mesquite trees, located near the canal, provide shade and help create a microclimate in the desert. Their presence contributes to biodiversity and fertility by improving soil moisture and nutrient levels, especially in the summer when they offer refuge from the harsh desert environment.