assessing subsurface hardpan and pond formation
DESCRIPTION
69th SWCS International Annual Conference “Making Waves in Conservation: Our Life on Land and Its Impact on Water” July 27-30, 2014 Lombard, ILTRANSCRIPT
the 69th Annual International Conference of the Soil and Water Conservation Society
Making Waves in Conservation: Our Life On Land and its Impact on Water‐Water Resources
Paper ID 97 : Assessing subsurface hardpan and pond formation using feature extraction technique in a sandy
irrigation Scheme, Eastern Saudi
YOUSEF ALRUMIKHANIKing Abdulaziz City for Science and TechnologyP.O.BOX 6086. Riyadh 11442. Saudi Arabia
E‐Mial: byaalrumi2kacst.edu.sa07/28/2014
Study Objectives.I. To o draw an attention to the problem of water logging in irrigated agriculture in Saudi
Arabia.
II. To demonstrate the causes of water logging in the center pivot irrigation scheme.
III. To determine and affirm the presence and distribution of the subsurface hardpan; which is the main cause of water logging in the affected irrigation scheme.
IV. TO develop an appropriate feature extracting technique that isolate the water logged areas of the irrigation scheme for further analysis
Location and Problem Statement
The elevation of the ground surface topography is highly variable and covered with light color sand dunes.
Geologically the area is part of the Arabian shelf with an undulating topography dipping northeasterly; that confirms with the regional trend.
The center pivot water logged irrigation scheme is
10 x 10 km2 (10000 ha.). It is located 47 km west of the Arabian gulf coast.
The location and nature of irrigation scheme
Problem Statement:The irrigation scheme consists of 79 center pivots, each 1‐kilometer diameter, utilized in grid patterns.
Original set up After water logging
Ponded Lakes
A5
A5
A6
A6
C6
C6
B5
B5
B6
B6
F5
F5
F6
F6
G6
G6
H6
H6
0 1000 2000 3000 4000 5000 6000 7000 8000
-400
-300
-200
-100
0
-400
-300
-200
-100
0
(depth in meters from sea level)FORMATION TAPPED IN SHADCO WELLS
SECTION NO.3, SHOWING UMM ER RADHUMA
Irrigation Water SourceCross Section showing Umm Er Radhuma Formation tapped in SHADCO wells
Sand Layer in Eastern Region is very thin With a high infiltration rate of 30cm/hour.
Causes of Water logging in Irrigation Scheme.
1- Imprevious layer.
Excessive irrigation is required because of high Evapotranspiration rate
Due to excessive Irrigation, Water can not percolate which results in the formation of ponds in low lying areas.
Cross-section showing the Impervious Layer (Marl)
The preliminary excavation in several parts of the project indicates a hard material (hardpan) underlined the irrigation scheme and causing the percolated irrigation water to rise upwards forming water logged areas.
SOIL SAMPLING RESULTS
SOIL SAMPLING LOCATIONS
SAMPLING DEPTHS. Centimeters
0‐15
15‐30
30‐60
60‐90
Clay % Silt % Sand % Grade F.C % P.W.P % Available Water % Hydraulic Conductivity. Mete/day5.4 13.5 81.1 Loamy sand 2.14 0.91 1.23 5
2‐ Soil Nature
0‐15 CM DEPTH
30‐60 CM DEPTH
60‐90 CM DEPTH
Hydraulic Head. cm
Hydraulic Head. cmHydraulic Head. cm
Hydraulic Head. cm
Hydraulic Conductivity of Site Soil(Permeability)
15‐30 CM DEPTH
SAMPLING DEPTHS. Centimeters
0‐15
15‐30
60‐90
WATER
PLANTSSOIL
AREA OF INTREST
Spectral Range. nm
Pancromatic 450‐800
Blue 450‐510
Green 510‐580
Red 650‐690
Infra Red 780‐920
GeoEye‐1 Satellite Sensor (0.46m)Date: 6/6/2011
Supervised Classification Technique
‐ Training stage: collect spectra from component.‐Classification stage: assign each pixel into a class‐Output Stage: Result clean up and output maps and statistics.
Feature Extraction Technique for the irrigation Scheme
Component Area. Ha Percentage. %WATER 2195.7 23PLANT 1147.5 12.8SOIL 6011 64.5
PLANTWATER
SOIL
‐Water conservation is a process that should be initiated at the very early stages of site selection and before project implementation.
‐Water wastage should not be only blamed on the natural features, but also on the inappropriate irrigation practices during project operation.
‐ Non‐availability of qualified professionals to manage this type of irrigation projects has significantly contributed to the problem.
- The installation of a drainage network in the project may require huge capital investments
- It is certain that continuing farming with center pivot irrigation systems, is not feasible.
- It is suggested that implementing drip irrigation for vegetable crops, with low irrigation water requirements, grown in green houses should be practiced.
- This sort of experience should add to the awareness and knowledge of the concerned specialist regarding the importance of a comprehensive reconnaissance survey of subsurface hardpan presence before the inception of irrigation projects.
Thank You.
The END