Assessment

Pre-Lesson Assessment

Pre-Quiz: Ascertain students' base understanding of the water cycle and hydrographs by asking them the

following multiple-choice questions.

Which of the following represents the movement of water from the oceans into the atmosphere?

Choose from: (a) runoff, (b) precipitation, (c) evaporation. Answer: (c).

Which of the following represents the movement of water from the land surface into the oceans?

Choose from (a) runoff, (b) precipitation, (c) evaporation. Answer: (a).

Which of the following represents the movement of water from the atmosphere to either the land

surface or oceans? Choose from (a) runoff, (b) precipitation, (c) evaporation. Answer: (b).

A hydrograph is: ________. Choose from: (a) an instrument used to measure streamflow, (b) a

map of stream gage locations, (c) a graph that plots streamflow. Answer: (c).

Post-Introduction Assessment

Real-World Calculations: See if students comprehend the application of the principle of conservation of

mass to water resource engineering by assigning them to solve mathematically the following problems (or work through them together, as a class). In these problems, students use the regional water balance

equation to estimate the amount of runoff leaving a watershed. By thinking of a watershed's water cycle as a closed system of inputs and outputs (inputs – outputs = storage), we (and engineers) can make

water estimates and predictions.

1. In a watershed that is 3.5 km2, the volume of annual precipitation was 5,000 m3 and the volume of water that was evaporated was 400 m3. Estimate the volume of annual runoff (m3). Assume that

storage and groundwater flux are negligible. Answer:

2. In a watershed that is 5 km2, annual precipitation was 20 cm and the evaporation rate was 0.01

cm/d. Estimate the volume of annual runoff (m3). Assume that storage and groundwater flux are negligible. Answer:

Lesson Summary Assessment

Discussion Questions: Before conducting the associated activity(ies), evaluate students' comprehension

of the lesson concepts through a class discussion. Example questions:

What are the primary components of the hydrological cycle (water cycle)? (Answer: Precipitation,

runoff/surface water, groundwater, evaporation, transpiration between the planet's atmosphere,

land and oceans.)

How does water move from the oceans into the atmosphere? (Answer: Evaporation.)

How does water move from the land surface into the oceans? (Answer: Surface water, runoff.)

How does water move from the atmosphere to either the land surface or oceans? (Answer:

Precipitation.)

What is a watershed? What is a hydrograph? Define in your own words the lesson vocabulary

words.

What types of data are plotted to create a runoff hydrograph? (Answer: To make a hydrograph,

we use surface water flow data collected at one location over a period of time. We plot the rate of

flow in volume/time units, such as cubic feet per second, on the y-axis, over time, on the x-axis.)

What is the difference between an event hydrograph and an annual hydrograph? (Answer: The

difference is the time period, short data collection for a storm event, perhaps minutes or hours, versus long data collection, perhaps years.)

What equations have we learned today and what do they describe? (Answer: We learned three

equations: conservation of mass, the regional water balance equation, and a simplification to the

regional water balance equation. Conservation of mass states that mass is conserved over time.

The regional water balance equation is a closed water cycle system that considers inputs and outputs of water. One simplification we can make is to assume groundwater has negligible

effects, thus we use precipitation and evaporation to estimate runoff.)

What do we mean by the regional water balance equation? (Answer: It's the regional closed water

cycle system in equation form: precipitation plus incoming groundwater minus the sum of leaving

groundwater and runoff equals storage. It puts all together the inputs and outputs in the watershed "system.")

How do engineers apply the principle of the conservation of mass to understand watersheds?

(Answer: Engineers think of the watershed as one closed water cycle system, with inputs, outputs

and storage amounts.)

For what purposes might engineers collect a watershed's streamflow data, make hydrographs

and use the regional water balance equation? (Example answers: To calculate a community's expected water needs [drinking water, sewage treatment, recreation, irrigation of crops, parks

and yards], to recommend whether water restrictions should be put in place during droughts, to

inform land owners of areas that are at risk of flooding, to design and manage dams and

reservoirs, to determine probabilities and statistics about potential flood scenarios, etc.)

Extension Activity: Have your students use what they learned and apply it to a real-world engineering problem. Pose the following scenario to your students:

Longmont, CO, is a town that sits at an elevation of ~5,000 ft above sea level to the east of the

Rocky Mountains and north of Denver, CO. The St. Vrain Creek, which is a tributary of the South

Platte River, flows right through the center of Longmont, CO. Starting on September 9, 2013, a

weather system stalled over this area of Colorado and dropped almost 20 inches of rain over the following week. To put this in perspective, this area of Colorado generally sees 20 inches of rain

over the course of an entire year. On September 12, streamflow reached 6,000 cubic feet per

second! The resulting Colorado Flood of 2013 was one of the worst recorded natural disasters

the state has ever seen. Imagine you are a Civil Engineer that works for the city of Longmont, CO

and answer the following questions:

1. Describe what the event hydrograph would look like for this event. [Answer: the event hydrograph

would have an x-axis with time spanning from Sep 9 to Sep 16 and a y-axis spanning from 0 to 6,000 cfs.]

2. Describe what the annual hydrograph that spanned January 2013 – December 2013 would look

like. [Answer: this would follow the general shape of the hydrograph in Figure 5 (showing

increased flow during the spring/summer months, however, in addition there would be a large

peak during the Sept 9-12 period as compared to any other flows throughout the year.]

3. As a Civil Engineer, you are tasked to develop ways for the city to be more prepared for a

flooding scenario in order to protect its citizens. What are some ideas for protecting against future

flooding? [Example ansers: (1) Fix the local floodplain map to make sure it is updated and to

better ready citizens for evacuation plans, (2) Model the flow and capacity of stormwater drainage to make sure it can handle a catastrophic event, (3) Use a computer model that will use the flow

of water upstream to estimate the flow of water at a point downstream so that we can have better emergency alert systems that eliminate 'flash" flood situations.]