I 3,l 2.3 5.4 *
Surface water dependenr;is consideredFringes of the NiSe Basin 0.7 0.2 0.3 a reservoir in the Nile systqm I
Desert Fringes t f
0.8 0.4 1.2 almost non-renewable
Subtotal pllikt Basin
I 4.6
2.9 7s
Nubian Sandstone 0.6 3,o 1 3.6 ‘ non-renewable
Coasta1
Aquifers
and Wadis 1 0.0 0.2 Iu*2 renewable
Subaotal autsidtt Nile. &sin 0.6 3.2 3.8 Additionaf to HAD flow
ofss.5 lo* &year
GRANDTOTAL
I 5261
11.3groundwater, rate of recharge and direction of natural vertical groundwater flow (see Table 2).
According to these parameters the Nile Delta region can be distinguished into four areas (see Figure 10).
1. The reclaimed desert areas with moderate to high vulnerable groundwater, due to the presence of sandy formations with high infiltration and low adsorption capacities, although groundwater is relatively deep.
2. The traditionally cultivated area with moderate to low vulnerable groundwater, due to the presence of a clay cap.
3. The transition zone between the old land (traditionally
cultivated) and the reclaimed areas with highly vulnerable groundwater, due to the presence of sandy soils and a shallow groundwater table.
4.The northern part with very low vulnerable groundwater, due to the presence of a top clay cap and upward groundwater flow.
The assessed impact of some pollutants on groundwater quality can be summarized in the following points:
1 *Most of the shallow handpumps appear to be contaminated with faecal coliform in the areas nearby domestic pollution sources (in the high vulnerable areas). This
LI thology Rrhrrgo Dlrtrltxrtlon Productlvlty Colour YalTD of
(rat two) &qulfW
SWfWO rub-rurfu~ syrtem
Grwl4r contlnuow cmtlnww utwln hloh dark blue Ntlr Basin
occwloN~ LImItad LocaL mderate ltght blue Ullr maIn,
to hleh Cout~l LON
. . . ..--.---
Me. Ilmltod l xtwulw adorate I!@n yrl\ou lloghrr
to high
fNfWftfCMt kdty utmlw IOU to dark yrllw IlUblWl
moderate swd8tocu
iNieniflcMt Ilalted tocat lo!d to light brown
modw8tr
. . . ..----.--
Plrwrod ud nme lad\y utoNiv~ modbratr tight green Cwbmatr
kwrtltld
!Nl#“ifkMt 1hlt.d loCaL IW PIti f I rrurd
bud rockr -
.-...-...
clay ti MN MN wnorrlly NW dark brom
ahalo
LO&
Figure 6. National hydrogeological map of Egypt.
98 Proceedings
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the UNESCO / NWRC /ACSAD Workrhopr on “Wadi Hydrology” and “‘Groundwater Protection ”Groundwater Protection in Egypt
Figure 7. Land forms and groundwater utilization map of Egypt.
faecal coliform counts decline rapidly with increasing screen depth.
2. In the reclaimed desert areas (moderate-high vulnerability), as a result of extensive use of fertilizers, concentration of nitrate increases (75-100 mg/l) and exceed the WHO drinking water standard (45 mg/l).
3. High nitrate concentration was found in sandy areas near sewage water irrigated areas (30-75 mg/l).
3.4.2 Vulnerability of groundwater to pollution in Greater Cairo Region
Following the same procedure, as in case of the Nile Delta, the groundwater vulnerability of Greater Cairo was assessed (Figure 11). Accordingly it can be concluded that:
1. Despite the very thin clay layer, the groundwater in the area east of Belbeis Drain has low vulnerability because the existing of upward seepage (discharge) from the aquifer. This discharge is mainly caused by extensive leakage from the Ismailia Canal which is located just in the high land.
2. Most of the groundwater in the flood plain has a moderate to low vulnerability to pollution. Exceptions concern two areas - one in urban Cairo and one north of Cairo - where the groundwater is more vulnerable due to locally thin covering layer combined with a larger sand fraction of the soil.
3. The high groundwater vulnerability exists in the fringes of the flood plain, where most of the agricultural land is located with some scattered rural areas. This is mainly due to the type of the aquifer (unconfined with relatively shallow groundwater).
The main sources of pollution in Greater Cairo Region are the following:
1. Common industrial activities are located at Shoubra El Kheima, Imbaba, Moustord and Helwan. Several private industries are spread all over Cairo. Assessment of impacts of the industrial pollutants still needs more investigations.
2. Agricultural pollution is mainly located at the western 99
I
Groundwater potential?I
tY
Where to pump groundwater and in which quantity, is a question which has to be solved before starting any groundwater development activity which complies with the national water resources policy. After construction of the wells, monitoring of abstractions and drawdowns is required to improve the management strategies. In this respect, the concept of groundwater potentiality has been proven to be very useful in the Egyptian conditions.
Groundwater potentiality is based on an integrated evaluation of the following parameters:
- aquifer type and its saturated thickness;
- productivity of the aquifer and rate of recharge;
- present and future depth to groundwater table;
- land use and existing abstractions;
- suitability of the groundwater for irrigation.
Groundwater potentiality depends on the quantity and natural quality of groundwater, Quantity refers to the availability of the source, while the quality refers to its suitability for a specific use (drinking water supply or agricultural use).
bank of the river Nile and north of Cairo. It results from In general, at various locations within the Greater Cairo the extensive use of fertilizers and pesticides. Region, most of the shallow wells for drinking water supply 3. Domestic pollution mainly originates from leakage of could be considered polluted either due to high salinity, iron
sewage networks in the served areas and from the content, or bacteriological contents.
drainage of sewage in the open channels in the areas
which depend on the septic tanks. The total and faecal 3.4.3 Pollution Load
colifonn are the indicators for this pollution. The pollution load depends on the land use of the area.
Figure 8. Potential for groundwater abstraction in West Nile Delta Region (1995).
Groundwater Protection in Egypt
ltrs 0‘ ra-cudmter Potential
for CevaQmlt #St cdta
Fringes
:6Wl ml’
,..,,.l,. ,.<.*. . . . . ..L.l
Ima’
,* I,,,,,,. *. ,.I... .*....*
iii’
I,,, ,I.. . . . .
Is3
,I, I.,... I,.. *a .I *....
Ii%
,,, I.,,,.,. .I.. 8. II *..*.
q I,, I.,. ,... a,.. I. ,* I..*.
Figure 9. Status of Groundwater Potential for Development West Nile Delta Fringes (I 995).
Table 2. Factors Afleeting The Groundwater Vulnerability in The Nile Delta
I
rtisal Rate of Depth to Groundwater Location
tdwater recharge groundwater vuherability , mm/day from surface (m)
0
o-2 0 O-10
>lO
Downward -
Downward >l
Downward <I
Downward Cl
C.5
5-15
>15
<5
!
Moderate-H!
o->lO
and reclaimed land Transition zone
I *
transition zone
Downward 0.25-l <5 Low
Upward ~25 <5 Low
Floodplain North Delta (Floodplain)
Figure 10. Groundwater vulnerability to pollution in the Nile Delta Region.
Table3 shows a qualitative indication for the pollution load considering different agricultural activities with different sources of irrigation water, industrial and urban activities.
3.4.4 Pollution risk
By combining groundwater vulnerability and pollution load, the pollution risk is established (Table 4). This pollution risk is a powerful indicator for determining priority areas for monitoring or intervention measures.
3.5 Monitoring network
The groundwater monitoring system in Egypt consists of the following components:
1. National groundwater level network (see figure 12):
consists of about 500 observation wells. (Data have been collected in the past 20-30 years.)
2. National groundwater quality monitoring network: the network is being updated at present. The design of the network is a stepwise process (see box).
Figure 13 shows the presently assessed priority areas for monitoring and the required density of observation points.
Location of the observation wells depends on the processes to be monitored (see figure 14).
Figure 11. Groundwater vulnerability in Greater Cairo Region
102 Proceedings
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Table 3. Classification of Pollution Load.
source Pdlutant