On-Site Challenge: Water Harvesting Terms and Concepts

Quiz 2(Use the terms & concepts list in the MESA Day Handbook along with the “Rainwater Harvesting for Drylands” resource book)

The upper limit of a body of groundwater is called a __________ __________

ANSWER: water table

DID YOU KNOW??• Water harvesting

structures such as berms & basins, holding ponds, & reservoirs hold the water in place allowing it to percolate into the ground thereby raising the local water table.

• Beaver dams raise the local water table too!

The wearing away of land by gravity, wind and water (& often a combination of these) is called _____?

ANSWER: Erosion

A beach cliff has collapsed due to a combination of water and gravitational erosion.

Topsoil is being eroded away by wind

True or False: Erosion can be intensified by human land use practices?

ANSWER: TrueExample: Without vegetation or other land use techniques to hold the soil in place, this roadside is quickly eroding due to water and gravity.

Look around your town for examples of erosion control features or places that need erosion control.

TRUE OR FALSE: Non-potable water is safe for human consumption?

ANSWER: False

• Though not drinkable, non-potable water (also called reclaimed water) is useful! Where are you creating non-potable water at home & school? Discuss ways you could re-use this water.

Monte Sagrado Hotel in Tao, NM uses reclaimed water to create a lush oasis at their resort.

Use of reclaimed water for artificial snow in ski resorts. Is this a good use? Research & find out why it is controversial!

An open or closed structure used for storing water is called a ___________?

ANSWER: Reservoir• Reservoirs often have multiple purposes: such as water

storage, flood control, recreation, and hydroelectricity creation.

• Discuss how you would incorporate good design planning and multiple uses for a reservoir if you were in charge of engineering a major water-harvesting plan.

Fishing in Abiquiu Lake Jet-skiing at Elephant Butte

Reservoir comes from the French word meaning “store house”

Elephant Butte Reservoir in Southern, NM- constructed between 1911-1916

Abiquiu Reservoir in Northern NM-constructed 1963

The surface area that rainwater lands on and is then diverted for beneficial use is called a

__________ _________

Rainwater being held for later use

Rainwater landing on a manmade surface area

?

ANSWER: Catchment Surface• NOTE: Catchment Surface areas can be man made, like the

roof in the previous slide, or natural; like the hillsides that funnel water toward the check dam below. Larger landscape areas that collect water are also called watersheds.

This diagram shows use of natural landscape features and urban features in a large scale water harvesting plan.

A more temperate or extreme localized climate created by the shelter or exposure of adjacent

landscape features or buildings is called a __________.

ANSWER: Microclimate• Notice the very different vegetation on these two

hillsides right next to each other! Discuss what you think is happening?

Shade and exposure to the sun can create a microclimate on a property. In general,

which side of the house in a hot New Mexico desert community could provide a cooler microclimate (north, south, east,

west)?

ANSWER: north side; this side will have the most shade throughout the day

Think About It…

Discuss how knowledge of a property or area microclimate can be applied to a rainwater harvesting plan?

How can the water that is harvested on a property be more wisely if you consider microclimates on the property?

Water that only flows seasonally or during and just after storms is called __________ ________ _____

ANSWER: ephemeral water flow

PHOTO: USGS Scientists installing instrumentation in an ephemeral stream at Abo Arroyo, New Mexico, to monitor streamflow and calculate recharge

MAP OF PERENNIAL (YEAR ROUND) STREAMS IN NM

MAP OF INTERMITTENT & EPHEMERAL (TEMPORARY) STREAMS IN NM

________ ______ is the rate at which water naturally fills or replenishes an aquifer.

ANSWER: natural recharge

There a various ways that scientists calculate natural recharge rates. Other factors must be considered when calculating the rate such as evapo-transporation, surface runoff, vegetation absorption of water, pumping of water in the local area, and more.

Water can be recharged naturally or artificially.

Artificial groundwater recharging thru pumping water back into the aquifer.

Passive artificial groundwater recharging by allowing the water to collect in a trench and percolate slowly into the ground.

A comprehensive water harvesting plan may involve both collecting water in holding tanks and cisterns for personal use AND designing areas to collect runoff to

recharge ground water!

The highest short-term volume of expected water flow is called:

A) Peak chargeB) Peak surgeC) Peak regeneration

Summer monsoon season drops a large volume of rain in a very short time frame. Photo: Animas Creek near Williamsburg, NM after rainstorm 9-13-2013

ANSWER: B) Peak Surge

• This homeowner installed a cistern that could collect the peak surge volume of water that could potentially fall during a rainfall “event” in their area.

A grey-water system that collects all household grey-water (kitchen sinks, bathroom sinks, washing machine, shower) should be designed to handle the peak surge, or greatest amount of water that could come thru the system at once.

SLOPE is the measurable ________ indicating a change in elevation

from one point to another.

A) altitudeB) steepnessC) slippage

ANSWER: B) Steepness

This yard has a very steep slope!

You are creating a water harvesting plan for a business site that has a very steep slope and can receive up to an inch of rain in a 1 hour storm. Which item/s do you need to consider for your plan?

A) Designing a plan to address erosion due to the steep slope.

B) Designing a plan that slows down the speed of water running down the steep slope.

C) Designing a plan that can accommodate the amount of water that will fall on the steep slope.

ANSWER: A & B• The steepness of the slope will increase the speed that

the water flows downhill and potentially cause greater erosion.

• The same amount of potential rainfall (up to one inch in an hour) will still land on the site, therefore the amount of water to accommodate remains the same.