water balance study - university of hawaiiclimate.socialsciences.hawaii.edu/courses/geog405/water...
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Water Balance Study:Manoa Valley Sept 2 to Nov 4, 2016
Tineill Dudoit - Shellie Habel - Madi MiyamuraShintaro Russell - Kenui Topp
Mānoa Valley● Site Area: Mānoa Valley, (11,187,443 m^2 ) faces along the South-eastern steep
slopes of The Koʻolau mountain range
● Experiences almost daily rainfall
● Differing gradients of elevation, climate, land uses, crops and soil types,
including native forests, thick vegetation and dense shrub/tree areas
Purpose - Estimate Water availability for Mānoa Valley case study area
- Gather other groups inputs and outputs from Mānoa valley case study
- Compute and complete water balance using ArcGis, totaling various
meteorological processes, parameters and estimated rates of water inputs
and outputs that affected Mānoa Valley and Mānoas water budget in total
From Sept 2 - Nov 4, 2016
Estimate Total Outputs
-Change in soil moisture
- Distributed groundwater recharge
- Distributed evapotranspiration (Canopy and surface/soil Evaporation)
source:https://laulima.hawaii.edu/access/content/group/2c084cc1-8f08-442b-80e8-ed89faa22c33/book/chapter_7/balance.htmSource:http://climate.socialsciences.hawaii.edu/Courses/GEOG405/GEOG%20405%20Water%20Bala
nce.pptx.pdf
AW = Available WaterAWC = Available Water Content*Root DepthGWR = Groundwater
INPUT DATA REQUIREMENTS (DAILY, WEEKLY, OR MONTHLY INTERVAL)P RAINFALL
RO RUNOFF
IRR IRRIGATION
PE POTENTIAL EVAPOTRANSPIRATION
INPUT PARAMETERSAMC AVAILABLE SOIL MOISTURE CAPACITY (EQUIVALENT WATER DEPTH PER SOIL DEPTH)
AWC = AMC * ROOT
ROOT ROOT DEPTH
SINIT INITIAL SOIL MOISTURE CONTENT
CF CROP FACTOR (COEFFICIENT TO ADJUST PE)
OUTPUTSEND SOIL MOISTURE CONTENT SOIL.OUT
RCHG RECHARGE RCHG.OUT
E EVAPOTRANSPIRATION EVAP.OUT
Available Water Capacity
★ Available Water Capacity is the difference between field
capacity which is the maximum amount of water the soil can
hold and the wilting point where the plant can no longer
extract water from the soil
Source:http://soilquality.org.au/
Available Water Capacity
★ Is the water held between field capacity and the wilting point
★ Is the maximum amount of soil moisture available for the ET
process.
★ Can be expressed either as a ratio or in water depth units
Available Water Capacity
Source:http://www.extension.umn.edu
Changes in Soil Water. Field capacity minus wilting point is the amount of water available to plants
Soil Types
1. rRt = Rough Mountainous Land
2. rCl = Cinderland
3. rRk = Rock Land
4. LoC = Lolekaa Silty Clay, 8 to 15 percent slope
5. LoD = Lolekaa Silty Clay, 15 to 25 percent slope
6. LoE = Lolekaa Extremely Stony Clay, 3 to 35 percent slope
Soil Types
7. LoF = Lolekaa Silty Clay, 40 to 70 percent slope
8. TAE = Tantalus Silt Loam, 15 to 40 percent slope
9. TAF = Tantalus Silt Loam, 40 to 70 percent slope
10. TCC = Tantalus Silty Clay Loam, 15 to 40 percent slope
11. HnA = Hanalei Silty Clay, 0 to 2 percent slope
12. HnB = Hanalei Silty Clay, 2 to 6 percent slope
Soil Types
13. HoB = Hanalei Stony Clay, 2 to 6 percent slope
14. MIA = Makiki Stony clay Loam, 0 to 3 percent slope
15. LoB = Lolekaa Silty Clay, 3 to 8 percent slope
AWC Values for each Soil Type1. rRt = Rough Mountainous Land AWC = 0.135
2. LoF = Lolekaa Silty Clay, 40 to 70 percent slope AWC = 0.110
3. TAE = Tantalus Silt Loam, 15 to 40 percent slope AWC = 0.120
4. LoD = Lolekaa Silty Clay, 15 to 25 percent slope AWC = 0.110
5. TAF = Tantalus Silt Loam, 40 to 70 percent slope AWC = 0.120
6. HoB = Hanalei Stony Clay, 2 to 6 percent slope AWC = 0.170
7. LoC = Lolekaa Silty Clay, 8 to 15 percent slope AWC = 0.110
8. LoE = Lolekaa Silty Clay, 25 to 40 percent slope AWC = 0.110
9. rRk = Rock Land AWC = 0.140
10. HnA = Hanalei Silty Clay, 0 to 2 percent slope AWC = 0.170
11. rCl = Cinderland AWC = 0.030
12. TCC = Tantalus Silty Clay Loam, 15 to 40 percent slope AWC = 0.110
13. MIA=Makiki Stony Clay Loam, 0 to 3 percent slope AWC = 0.140
14. LoB=Lolekaa Silty Clay, 3 to 8 percent slope AWC = 0.110
15. HnB=Hanalei Silty Clay, 2 to 6 percent slope AWC = 0.170
Putting Together the Parameters★ Imported a shapefile from nrcs.usda.gov into ArcGIS
★ This geospatial file contains the different types
within our watershed
★ ArcGIS takes these soil types and splits them into
polygons and separates them into each grid cell
Putting Together the Parameters★ Divide the soil type area by the total area within
each cell to get the % soil type in each gridcell
★ AWC for each soil type can be found in the Soil
Survey of the State of Hawaii
★ Multiply the AWC to the % soil type(s) in each grid
cell
Putting Together the Parameters★ The AWC for each soil type in each grid cell is then
added together for a weighted average of AWC in
each grid cell
★ The values for weighted average of AWC in each
grid cell is used as a parameter in the Water Balance
Model
Putting Together the Parameters: geospatial files ✓ AMC
❏ Root Depth
❏ Crop Factor
Root DepthPer Square:
Root depth x % paved +
Root depth x % forest =
Weighted Average Root Depth
% AWC x weighted root depth =
Depth of water
Crop factor A correction factor for ET
→ land covers/crop that is not under “standard conditions”
→ excellent soil moisture, conditions etc.
(Crop factor x % paved) + (crop factor x %heavily forested) + (crop factor x %
forested) = Weighted
Irrigation
Used an Irrigation water balance file off of USGS
Blue = 0 ( NO irrigation)
Colored= 1 (Irrigation)
Modeled Soil Moisture vs Observed Soil Moisture
Total Precip (mm)
Total Potential Evap (mm)
Total Actual Evap (mm)
TotalRunoff (mm)
Total Recharge (mm)
Precipitation-Recharge Threshold
Precipitation-Recharge Threshold
Average TotalDepth Per Cell (mm)
Volume (m^3) Volume (gallons)
Precipitation 916 1087532 290 million
Evaporation 163 192967 51 million
Runoff 437 518564 137 million
Recharge 325 385639 102 million
Manoa Watershed Totals
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Giambelluca, T.W., X. Shuai, M.L. Barnes, R.J. Alliss, R.J. Longman, T. Miura, Q. Chen, A.G. Frazier, R.G. Mudd, L. Cuo, and A.D. Businger. 2014.
Evapotranspiration of Hawai‘i. Final report submitted to the U.S. Army Corps of Engineers—Honolulu District, and the Commission on Water
Resource Management, State of Hawai‘i.