Water Management Strategies and Management of Aquifer Recharge
A) CSA Conceptual Flow model of the 5.7.1 Geology and Lithologic construction of conceptual model
5.7.4 Ground water recharge and discharge: Water Balance (inflow/ outflow)
Inflow (Recharge): A comparative analysis of inflow (recharge) and outflow (discharge) from aquifer balance was calculated in this contest. Long term average of recharge should equal discharge unless significant change in storage occurs. Therefore, recharge source in this model is concerned with three main sources taking into consideration the negligence of a few quantities of annual average rainfall (< 140 mm) with very high evapotranspiration (2,500 mm/year). These sources are:
- Recharge from wadis run off: there are three main wadis in the Jericho model area: Auja, Nui’meh and Qilt. The run off of these wadis was estimated at 10% of the annual flood. This surface run off is affected by rainfall intensity, soil type and catchment slope. So, Auja catchment is 291.1 km2. Usually, Wadi Auja in a rainy year has about 3 MCM of surface water runoff. The assumed recharge from infiltrated run off to shallow aquifer equals about 10% of total run off (0.3 MCM/a).
- Return flow from applied water, irrigation system: Figure 5.22 (a,b) shows the monthly CWR and LR, about 35% (From Chapter 3). This helps estimating infiltration rate by 20% of
ClECNaTDS 0
5000
Cl EC Na TDS
0
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
CWR Mm³/Area.mont
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
LR of current Agriculture Accumelated LR
up area. Leakage also occurs from conveyance by canals to several springs. Such example of Auja canal loss of about 50% of its discharge through the wadi before being conveyed by open and damaged cement canals in different places along the canal is another source. By this system about 10% of conveyed water of spring discharge infiltrates. In addition, effluents of different Auja clusters, Nui’meh and Jericho are considered actual. Thus loss of domestic water network is about 25%. This quantity is indeed distributed in buildup area where people are assumingly clustered in the CSA. About 10% of lost quantity infiltrated
(a) (b)
Figure 5.22,a: Monthly and accumulated CWR in the CSA; Figure 5.23.b shows the LR of current agriculture and accumulated LR in the CSA.
Return Flow from domestic network and waste water effluents in the CSA
In accordance with the recharge in terms of received domestic water (DW) and Waste Water Effluents (WWE), and as mentioned before in Chapter 4 (Sec.4.2.2), the total received domestic water from Auja Municipality Council is 367,398 m3 per month. The old network leaks about 30% of this DW quantity. Estimated recharge of this leakage does not exceed 10% based on soil properties and evapotranspiration calculation (Chapter 3), so the total recharge from DW network is 112,194 m3.However, it does not present a convenient recharge source in the buildup area. On the other hand, WWE recharge forms about 50% of WWE from permeable cesspits system that receives WWE in house hold level. The recharge quantity by WWE is estimated at146,959.2 m3/a. However, Table 5.5 illustrates all these results.
Table 5.5 Part 1: DW recharge and WWE recharge at the CSA (2012-2013)
Date
Table 5.5 Part 2: DW recharge and WWE recharge at the CSA (2012-2013)
Apr.2013 29431 8829.3 882.93 23544.8 11772.4
May 2013 31916 9574.8 957.48 25532.8 12766.4
June 2013 37673 11301.9 1130.19 30138.4 15069.2
July 2013 49193 14757.9 1475.79 39354.4 19677.2
Aug. 2013 35918 10775.4 1077.54 28734.4 14367.2
Sep. 2013 30446 9133.8 913.38 24356.8 12178.4
Oct. 2013 31414 9424.2 942.42 25131.2 12565.6
Nov. 2013 31941 9582.3 958.23 25552.8 12776.4
Total 367,398 110,219.4 11,021.94 293,918.4 146,959.2
Lateral flow from mountains: Recorded historic data of water table of the wells in the CSA reflect recharge rate and recharge quantity in this model. They indicated monthly increase of water table throughout 38 years (1967-2005) by about 2 m increase in water table. Figure 5.23 illustrates water table variation regarding Well No. 19-15/005 friom1967 to 2005, and the same in several major wells in the CSA. This increase is very clear in wet years and after precipitation events along 4 to 5 months in every wet year. This could explain the lateral flow from mountains in the CSA.
Figure 5.23: Monthly water table time series of observed Well No. 19-15/005 in the CSA.
In 2000, Millennium Engineering Group (MEG), estimated water quantity which leaves the mountain Aquifer by 19 MCM. This water recharges alluvial lenses in areas by direct contact where fractures exist. It is well known that Jericho area is close to Turonian springs which means that most of the southern part of the valley Rift Fault boundary between alluvial deposit and mountain aquifer acts as a barrier (Jericho Model, 2000). It is the southern boundary of Jericho area. But on the CSA Area in Auja area, the recharge occurs north of Wadi Nui’meh and south of Auja area. In the context of recharge estimation in the CSA, the
and by referring to Water Table Fluctuation (WTF) methodology (Healy, R., Cook, P. 2002, using groundwater levels to estimate recharge, (Hydrogeology Journal 10, 91-109), recharge is estimated as:
R (t) = Sy* ∆H/ (t) ……… (5.1) Where;
Where R (t) = recharge rate, Sy=specific yield (dimensionless)
∆H=the drop of head pressure in time period
(t)=The time interval of water flocculation hydrograph
In our CSA, Sy is estimated from 0.01 to 0.0025 in alluvial deposit, ∆H is 2 m which that based on historic data and observed wells hydrograph, and the estimated recharge rate is between 0. 015 m/day and 0.02m/day in the time period. So, the recharge rate from mountain lateral flow in the CSA regarding average yearly rainfall in the upper catchment (600 mm/y) is about 0.1 Mm3/year. In Shallow aquifer, by referring to several resources, run off, return flow, and mountain lateral flow, the estimated recharge is 0.3 Mm3/y, 0.8 Mm3/y and 0.1 MCM/year respectively in addition to 0.16 Mm3/a from DW and WWE recharge. So, the total recharge in the CSA in shallow aquifer is about 1.36 MCM/ground water outflow (Discharge): In CSA, Most water discharge has two main sources: the shallow alluvial wells and deep carbonate aquifer, which is Auja Spring discharge. Details of the two main sources are as follows: Shallow wells in Jericho District are 49 wells, with only 35 working ones.
Figure 5.24 Extraction from these wells has sharply decreased during the period 2001 to 2009 from about 6 Mm3/a to 2.1 Mm3/a in 2009.
Figure 5.24: Jericho wells extraction during the period from 2001 to 2009. (PWA, 2013)
6.18531
2001 2002 2003 2004 2005 2006 2007 2008 2009
Mm³
Abstraction of 35 Agr. wells
Year(Mm³) Agr. Wells(35 well) Poly. (Agr. Wells(35 well))
In the CSA, there are 10 working wells with a monthly extraction of about 1.02 mcm/a in wet years and 0.51 mcm/a in dry years. This model of worst case scenario of drought (Figure 5.25) displays monthly mean extraction of Auja wells in both dry and wet years.
During dry years many of those wells stop working. Therefore, the month with heavy extraction is during summer season, when evapotranspiration is very high.
Very little quantity of spring discharge will reach the irrigated area. Figure 5.25 and table 5.6 illustrate the wells monthly abstraction in the CSA.
Figure 5.25: Monthly mean abstractions of Auja wells in both dry and wet years.
Table 5.6: Monthly mean abstractions of Auja wells during both wet and dry years Total mean Abstraction
In the CSA, and from mountain foot, Auja Spring (the largest spring in the LJV) is located in the karstic system aquifer and is formed from deep carbonate discharge with 8.61 Mm3/a as
0
cement canal. The remaining quantity loses 50% because of damaged canal and its branches and by the irrigation system in the area. Only 2.15 Mm3 are received for irrigation purposes.
Figure 5.26 shows historic hydro graphic of Auja Spring discharge and rainfall from Dir Dibwan weather station.
Figure 5.26: Auja Spring historic hydrograph (1974-2013) and historical rainfall records.
As shown in Table 5.7, total inflow of water into both alluvial shallow and deep aquifer is about 7.445 Mm3/a, with only 1.46Mm3/A of total inflow goes to the aquifer. It is assumed that 0.439 M Mm3/a of storage inflows from subsurface of alluvial to Lisan formation.
Therefore, the total abstraction from shallow aquifer based on wet years does not exceed 1.021 M Mm3/a explainable by increased salinity of shallow aquifer in dry years in case of overexploitation coning from saline Lisan formation to alluvial deposit, in particular. Mean outflow from Auja Spring comes from deep carbonate aquifer; it is 8.12Mm3/a as yearly mean discharge. This quantity of discharged water is distributed between irrigation (1.679 Mm3/a), and return flow into shallow and deep aquifer. Part of this quantity also flows by Wadi Auja to the River Jordan, especially during flood days and in general during winter.
Table 5.7Part1: Inflow-outflow balance, discharge and recharge in the CSA
Balance in Discharge and Recharge Recharge /Discharge (Mm3/a)
Remarks
Inflow Wadi Auja Runoff 0.3 Shallow Aquifer
Return flow from spring flow into irrigation canals 0.8 Shallow Aquifer
Return flow from DW 0.11 Shallow Aquifer
Return flow from WWE 0.15 Shallow Aquifer
Return flow from spring losses into wadi to deep aquifer
3.83 deep aquifer
and Jordan River Return flow from canal into deep aquifer 2.155 deep aquifer
1263.0895
1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Dir Debwan Station Discharge/100 (MCM/a)
Table 5.7Part2: Inflow-outflow balance, discharge and recharge in the CSA
Lateral flow from Mountain Aquifer 0.1 Shallow Aquifer
Total inflow into both deep and shallow aquifer 7.445 Both deep and shallow aquifer Total inflow into shallow aquifer 1.46 Shallow aquifer Inflow
into shallow
aquifer
Subsurface in flow from alluvial to Lisan -0.439 Shallow Aquifer (storage in
Lisan) Out
Flow
Abstraction from wells 1.021 Shallow
Aquifer Discharge from Auja Spring (Deep Aquifer) 8.61 Deep Aquifer Total out flow from both deep and shallow aquifer 9.12 Both deep and
shallow aquifer Total out flow from shallow aquifer 1.021
Differen calculate water flow budget in the CSA regarding the current situation of water budget.
Several scenarios were suggested based on IWRM in the CSA.
Predicting water budget for next decades took into consideration the climate change impact in