Lab 2

BRAE 340 Irrigation Water Management 1 Flow Measurement BRAE 340 Irrigation Water Management Lab – Flow Measurement Name: ______________________________ Date: _______________________________ BRAE 340 Lab: Day: ____________ Time: ___________ Names of Others in Your Discussion Group: _________________________________ _________________________________ _________________________________ _________________________________ _________________________________ _________________________________

BRAE 340 Irrigation Water Management 2 Flow Measurement Flow Measurement Introduction The goal of this lab is to give you some experience with different types of water measurement devices. Water measurement is important because it is difficult to manage a resource if you have no idea what the flow rate is or how much (volume) of the resource has been used. Irrigation districts in many cases must be able to measure water in order to deliver and bill for the correct amount. Farmers must understand flow rate and volumes to effectively manage their irrigation systems and schedule irrigations. As you work with the different devices, think about how each measurement might be more or less accurate than the others, and under what conditions this might be so. Read the instructions and questions below before completing the lab. Lab Preparation Watch the tutorials and lab videos on Canvas prior to completing the labs. You will use data that you must collect from the Part 2 video to answer the questions and determine the flow rate for each device. Field Work While the canal is still dry, take all the measurements necessary to describe the size of that device. The instructor will start the flow through the canal and adjust the valve at the meter gate as necessary. Once the flow rate has stabilized, take the measurements necessary to estimate the flow through each device. Data Collection Use the Data Collection and Analysis forms below to record the values for your measurements that you will get from the videos. Data Analysis Use the flow rate tables (on Canvas) to determine the flow rate through each device. Draw a bar graph illustrating the results of your calculations on the grid area provided (after the Data Collection and Analysis forms). Learning to plot your graph in Excel would be a very useful skill to have – try it! Discussion Questions Think about the questions at the back of the lab. Write your own answers to the questions in the space provided. Grading • Participation (5%) • Data Collection & Analysis (55%) • Discussion Questions (40%) Useful Conversion Factors • 1 acre-foot = 43,560 cubic feet • mm ÷ 25.4 = inches • GPM ÷ 448.8 = cfs • inches ÷ 12 = feet • Gallon ÷ 7.48 = cubic feet I 9 p m = 4 4 8 . 8 4 s

BRAE 340 Irrigation Water Management 3 Flow Measurement Data Collection and Analysis Magnetic Meter (10 pts) Flow Rate (Direct Reading) Flow Rate (large number): ________________ GPM = _____________________ CFS (Meter Reading) (Computed) Calculated Flow Rate (Volume /Time) Start of Lab (Volume) Meter Reading at Start of Lab: ____________________ gal @ Time (Start): ____________ End of Lab (Volume) Meter Reading at End of Lab: _____________________ gal @ Time (End): ____________ Volume Pumped & Duration of Pumping Duration = Time at end of Lab – Time at start of Lab Duration: _____ min _____ sec Convert to seconds Duration: ___________ seconds Volume = Reading at End of Lab – Reading at Start of Lab ____________________ gal - ____________________ gal = _________________ gallons Convert to cubic feet Volume = ____________ cubic feet Flow Rate Average Flow Rate (cfs) = Volume (cu-ft) ÷ Duration (sec) ____________ ÷ ___________ = ___________ CFS Metergate (5 pts) Determine the flow rate using the provided table. H = head measured in millimeters (use the stilling wells) Stem Height (valve open): __________ mm Upstream Height: _________________ mm Stem Height (valve closed): _________ mm Downstream Height: _______________ mm Valve Opening: ________ mm Head Difference: _______ Flow Rate = __________CFS Head Concrete Canal Inlet Pipe A S t h i d p a s s e s t h r o u g h t h e p i p e , a v o l t a g e d i r e c t l y p r o p o r t i o n a l t o t h e f l o w r a t e i s g e n e r a t e d . + 1 - 2 % e x . f l a s h i n g 1 0 0 0 9 p m 1 2 3 4 5 6 7 8 9 g a l l o n s s t a r t ? 1 2 3 4 5 9 7 8 9 e n d = 3 0 0 0 g a l i n ✗ t i m e s h o u l d = f l o w r a t e . 1 5 5 6 5 9 0 3 5 2 . 3 9 m ¥ x , 4 8 5 4 , = 4 7 . 0 9 8 9 3 5 2 . 3 - c o u l d n ' t q u i t e t e l l 5 5 1 5 1 8 . 3 9 6 5 6 2 6 0 5 . 8 2 2 3 1 m i n ✗ 6 0 s e c / m i n = 1 8 6 0 + 2 2 0 : 0 0 4 1 0 0 . 8 1 5 1 5 3 1 : 2 2 3 1 2 2 1 8 8 2 5 6 2 6 0 5 . 8 2 2 5 5 1 5 1 8 . 3 9 6 1 1 0 8 7 . 4 2 6 1 4 8 2 . 2 8 1 1 0 8 7 . 4 2 6 7 . 4 8 = 1 4 8 2 . 2 8 1 4 8 2 . 2 8 1 8 8 2 0 . 7 8 7 1 0 5 0 . 7 8 5