Hydrologic Cycle, Part 2

Hydrologic Cycle, Part 2

Review components of the hydrologic cylce through discussion of images

Hydrology Fundamentals

• Rule 1: Water is the most powerful force on Earth

• Rule 2: Nature WILL have the last word

Multiple Select

How do the two dam failures (Teton Dam & Edenville Dam) compare? (Choose all that apply)

• both were earthen dams

• both were compromised by seepage and piping

• both were the result of poor or improper inspection

• both caused catastrophic damage downstream

Pipe Sizing

Make note of the size of this pipe compared to the workers standing next to it.

Sizes of pipes are influenced by how much water needs to be moved.

Multiple Select

What are the purposes of the features shown in this picture? (Choose all that apply)

• to slow down water; dissipate energy

• to speed up the water; increase energy

• to promote infiltration

• to filter out debris

• to create a dam to stop water from going down the hill

Multiple Choice

What is the purpose for the stones seen here?

• for aesthetics

• to create a dam (or barrier) separating the pool from the pipe

• to dissipate energy and reduce scour

• to re-route the water away from the neighborhood

Multiple Choice

Can a pipe be considered one of the hydrologic cycle features?

• Yes; it provides both movement and storage

• No; it is not one of the components listed during the previous discussion

Multiple Choice

How is this a useful feature in the hydrologic cycle?

• it is a permanent feature intended to slow and filter runoff

• it is a temporary feature intended to slow and filter runoff

• it is intended to swell during high flow events and shrink during lower flows

• it is not a useful feature

Multiple Choice

What might cause this slope failure?

• loss of vegetation that holds the slope together

• gradual erosion by wind

• the weight of the vegetation itself

• infiltration and saturation of the underlying soil

Slope failures

This appears to be a recurring theme. Water movement through the vadose zone causes fluctuations in soil moisture. Similar to the dam failures, if sufficient soil moves (flows) then the overburden of the soil will cause failure.

Multiple Choice

In any developed area semi-pervious and impervious surfaces are part of the landscape. What are some concerns, from a water perspective, of these surfaces (like parking lots)?

• quickly moving water away from a flood-prone area

• contaminants that are present may be mobilized and compromise water quality

• too many parking lots are an eye-soar

• parking lots provide above ground storage

Man-made or Natural?

Unlike some of the other images shown, this is the result of a debris flow. Rock and sand intended for another purpose left the upstream site with the water and is scattered along this hillside.

Preface for the vide that follows on building dams

Multiple Choice

Flood Hazard Areas: How does the delineation of the flood hazard affect development of the area?

• It has no affect; development still occurs despite any known hazards

• development of the area is avoided whenever possible; contingencies are put in place in case of flooding

• development of the area is not done out of safety concerns

Depending on the conditions of the two rivers (temperature differences, sediment/density differences, energy/flow), mixing may not occur!

Multiple Choice

Is this a concern during a rain event? It appears to be several chemicals present on the pavement

• Yes, this will be mobilized by the runoff

• No, these will likely stick to the pavement

Multiple Choice

Is this a concern during a rain event? It appears to be leaves that fell from nearby trees

• Yes, this contributes to organic contamination of our streams

• No, leaves naturally fall down and are decomposed in our environment

Multiple Choice

Is this a concern during a rain event? It appears to be deicing salt on the sidewalk

• No, it is just salt and not some harmful chemical

• Yes, salt will wash into the sediment and streams and cause dehydration of roots and increased salinity of streams