Precipitation in Manoa Valley Adrianna, Felise, Olivia, Austin & - - PowerPoint PPT Presentation

Precipitation in Manoa Valley

Adrianna, Felise, Olivia, Austin & Hannah

P + CWI + IRR

Precipitation, cloud water interception, and irrigation provide the ability for runoff and evapotranspiration to occur.

Introduction

Objectives..

• Attain data from input sources:

Precipitation, Cloud Water Interception and Irrigation

• Two site stations:

○ Lyon (upper) ○ Mauka (lower)

• Rainfall monitored September 2nd-

November 4th, battery died towards the end which affected later values

Daily Rainfall Compared...

Mean monthly rainfall from the Atlas of Hawaii compared to the classes recorded data...

Methods

• Divided Manoa valley into 3 different

sections to split up surveying (upper, lower and mid valleys)

• Walked door to door surveying anyone that

would talk to us in each section

• Asked about watering habits, and

approximate square footage of lawn

• Used the bucket method to find water flow

from a hose, and applied that to square footage of lawn/garden

• 1. Do you water your yard?

a) Yes b) No (if answered no, do not continue)

• 2. Do you water your yard with a hose or with

sprinklers? a) Hose b) Sprinklers c) Both

• 3. If you use a hose, on average how long does it

take you to water your yard? a) 1-10 minutes b) 10-20 minutes c) 20-30 minutes d) 30-40 minutes e) 40+ minutes

• 4. If you use a hose, what pressure does the hose run?

a) full pressure b) half pressure c) low pressure

• 5. If you use sprinklers, on average how long do your

sprinklers run? a) 1-10 minutes b) 10-20 minutes c) 20-30 minutes d) 30-40 minutes e) 40+ minutes

• 6. About how many days out of the week do you water

your yard? a) 1-2 days b) 3-4 days c) 5-6 days d) Everyday

• 7. What is the approximate square footage of your yard

space? ______________________________ sq ft. Thank you for your time!

Methods Cont..

Irrigation: Bucket Method Measured the volume of a cooler= 47.3 Liters Used a stopwatch to measure the time it takes in minutes for a hose to fill the bucket at different pressure Took the average of multiple trials of filling the bucket Average low pressure: 6.23 minutes Average high pressure: 1.32 minutes Divided the volume by the time it took to fill the bucket to find the flow rate Low pressure flow rate: 7.59 liters per minute High pressure flow rate: 35.83 liters per minute

Irrigation Survey Sites

Upper Valley

(21.329268, -147.803212)

Mid Valley

(21.315804, -157.810981) (21.308989, -157.802010)

Lower Valley

(21.306758, -157.820975) (21.305442, -157.813220) (21.308000, -157.816139)

Proposed Irrigation Area

• Upper & mid valley zero irrigation
• Blue shaded area indicates proposed

irrigation area

11,187,443m^2 = Total Watershed Area 58,573m^2 = Each grid square Total approx area of irrigation zone = 1,464,325m^2

• 2.49mm of Irrigation per grid

25 grids x 2.49mm = 62.25mm 62.25mm of irrigation is added to the inputs of the water balance for the recorded time period.

Methods Cont..

Interpolation Methods

• Normal Ratio
• Inverse Distance Weighting

Cloud Water Interception

• Determined which grids were above 2,000 ft
• Used leeward side ratio values for each

month Measurements

• Distance: Km
• Rainfall: mm

CWI Map

• CWI forms in grids 50% or more above the

blue line

• The blue line is a contour line of 2,000ft
• CWI only affects 7.8% of our watershed

GRAPH TWO

Total Precip: Entire Watershed

• Upper Valley = 626,547m^3
• Mid Valley = 210,747m^3
• Lower Valley = 250,618m^3

Total Precipitation: 1,087,532 m^3

FINAL FIGURES

Total CWI: 30,218.43 m^3 Total IRR: 91,154.23 m^3

Results

➔

The results show ➔

• Rainy season in September

➔

• Dry season in October

➔

• More rainfall at Lyon then the monthly

mean values ➔

• Little to no CWI influence

➔

• Irrigation has a small role in water

balance, none in the middle and back

• f the valley

➔

Summary

• Precipitation is vital to the water cycle
• NR and IDW method to interpolate

grids

• Ratio method for CWI
• September experienced high rainfall
• It was much drier in October
• The upper valley only experiences CWI
• The lower valley only has irrigation

Bibliography

• Engott, J.A., Johnson, A.G., Bassiouni, Maoya, and Izuka, S.K., 2015, Spatially distributed groundwater recharge for 2010

land cover estimated using a water-budget model for the Island of O‘ahu, Hawai‘i: U.S. Geological Survey Scientific Investigations Report 2015–5010, 49 p., http://dx.doi.org/10.3133/sir20155010.

• Giambelluca, Thomas W, Qi Chen, Abby Frazier, Jonathan Price, Yi Leng Chen, and Pao-Shin Chu. 2013. “Online Rainfall

Atlas of Hawaii,” no. March: 313–16. doi:10.1175/BAMS-D-11-00228.1.

• Frazier, Abby G, Thomas W Giambelluca, F Diaz, and Heidi L Needham. 2016. “Comparison of Geostatistical Approaches

to Spatially Interpolate Month-Year Rainfall for the Hawaiian Islands” 1470 (August 2015): 1459–70. doi:10.1002/joc.4437.

Over to you RUNOFF!