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UTC: 631.4:452: 633.2
COMPREHENSIVE HYDROECOLOGICAL ASSESSMENT OF WATER
RESOURCES AND MELIORATION IMPACTS IN THE ARAL SEA
Za a jon Jabba o , S.Mahammadiye , K.S.Idi iso ,U ol Nomozo O amu od Imomo 1,
Shoh uh Abdullaye 1
1Na ional Uni e si y o Uzbekis an named a e Mi zo Ulugbek, Uni e si y S ee , 4, 100174
Tashken , Uzbekis an
2Sama kand S a e Uni e si y o Ve e ina y Medicine, Animal Husband y and Bio echnology,
Tashken B anch, Uzbekis an
[email p o ec ed], [email p o ec ed], mu оd.imоmо 2019@gmаil.cоm,
shоxаbdullае 1996@gmаil.cоm
DOI: h ps://doi.o g/10.5281/zenodo.17537557
Abs ac : This s udy p esen s a comp ehensi e hyd o ecological e alua ion o wa e
esou ces and he e ec s o melio a ion on he i iga ed landscapes o he Republic o
Ka akalpaks an, loca ed A al Sea d ied bo om. A e ined landscape geochemical me hod was
de eloped o assess hyd o ecological s a us a he scale o small i iga ion basins. This app oach
enabled he quan i a i e and quali a i e cha ac e iza ion o i e , collec o -d ainage, and
g oundwa e sys ems imp o ing he p ecision o egional wa e balance assessmen s and quali y
moni o ing. Findings demons a e a signi ican spa ial a ia ion in wa e mine aliza ion
( anging om 0.5 o 10 g/L), ha dness (8.5–160 mg-eq/L), and ion composi ion domina ed by
Cl⁻ and SO₄²⁻ ions. G oundwa e salini y and dep h luc ua ions ac oss indica e p og essi e.
Recommenda ions o eusing collec o -d ainage wa e s o i iga e sal - ole an c ops and
eclaim highly saline soils ha e been in eg a ed in o he egional wa e managemen sys em,
suppo ing sus ainable use o limi ed wa e esou ces unde clima e a iabili y and A al Sea
desicca ion impac s.
Keywo ds: Hyd o ecology, melio a ion, mine aliza ion, g oundwa e , collec o -d ainage
wa e , A al Sea basin,
1. In oduc ion
The Republic o Ka akalpaks an, loca ed in he lowe eaches o he Amu
Da ya Ri e and adjacen o he A al Sea basin, ep esen s one o he mos
hyd oecologically ulne able egions o Cen al Asia (UNEP, 2020; Micklin,
2016). Ex ensi e i iga ion and melio a ion p ac ices, ini ia ed du ing he 20 h
cen u y, ha e caused la ge-scale changes in hyd ological egimes, wa e salini y,
and soil deg ada ion. The d ying o he A al Sea, combined wi h educed i e
in low and excessi e g oundwa e ex ac ion, has led o he in ensi ica ion o
seconda y saliniza ion, de e io a ion o wa e quali y, and he ans o ma ion o
del aic ecosys ems (Molden e al., 2007; FAO, 2018).The cu en s udy aims o
assess he hyd oecological condi ion o su ace and g oundwa e sys ems, analyze
spa io empo al dynamics o mine aliza ion and salini y, and iden i y managemen
pa hways o op imizing wa e use e iciency in i iga ed and eclaimed lands.
2. Ma e ials and Me hods
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2.1 S udy A ea
The s udy co e s he lowe A al Sea basin, including he Muynak dis ic s o
Ka akalpaks an, he Amu Da ya del a, and pa s o he A al Sea d ied bo om (A al
sea Dese ). These e i o ies include ex ensi e i iga ed ag icul u al lands and
collec o -d ainage ne wo ks connec ed o he main channel and i s ibu a y
sys ems.
2.2 Key Indica o s
Measu ed pa ame e s included i e discha ge, mine aliza ion (g/L), o al
ha dness (mg-eq/L), dissol ed oxygen, pH, dominan ion composi ion (Na⁺, Ca²⁺,
Mg²⁺, Cl⁻, SO₄²⁻, HCO₃⁻), g oundwa e dep h, and collec o -d ainage low
cha ac e is ics.
2.3 Analy ical Me hods
A combina ion o hyd ochemical and GIS-based mapping me hods was
employed. Long- e m obse a ion da a (1963–2019) we e p ocessed using
co ela ion and eg ession analyses o iden i y ends and causal ela ionships
be ween i iga ion in ensi y, g oundwa e le els, and salini y. The landscape–halo-
geochemical me hod was e ined o egional hyd oecological assessmen
(Ka imo e al., 2019; Ka akalpaks an Minis y o Wa e Resou ces, 2020).
3. Resul s and Discussion
3.1 Hyd ological and Hyd ochemical Regime
Analysis o hyd ological da a shows ha he Amu Da ya’s discha ge has
dec eased 1.3–1.6 imes be ween 2000 and 2012 compa ed o ea ly 20 h-cen u y
eco ds. The i e ’s chemical composi ion is domina ed by chlo ide and sul a e
ions, ollowed by sodium, calcium, and magnesium. To al mine aliza ion eaches
up o 2–3 g/L in a e age yea s, inc easing owa d he del a egion due o
e apo a ion and d ainage in low.Seasonal a ia ions indica e maximum salini y
du ing low- low pe iods (July–Sep embe ) and minimum du ing high- low mon hs
(Ma ch–Ap il). These luc ua ions co espond o i iga ion cycles and he iming o
leaching and d ainage p ocesses.
3.2 Collec o –D ainage Sys em and Melio a ion E ec s
Fi een majo collec o s discha ge app oxima ely 2.2 km³ o saline wa e
annually in o he Amu Da ya del a (Ka akalpaks an Minis y o Wa e Resou ces,
2020). The mine aliza ion o collec o -d ainage wa e s anges om 1.7 o 3.9 g/L,
p edominan ly o chlo ide–sul a e–magnesium–sodium ype.Du ing high-wa e
yea s, discha ge olumes inc ease, while mine aliza ion dec eases, indica ing he
dilu ion e ec . Con e sely, in d y yea s, educed low in ensi ies sal accumula ion
and e u n low con amina ion.These indings con i m he s ong dependence o
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i iga ion wa e quali y on ups eam low a ailabili y and managemen e iciency,
consis en wi h ea lie s udies by Molden e al. (2007) and Do an & Ka len (1994).
3.3 G oundwa e Dynamics and Salini y
G oundwa e dep hs ac oss i iga ed lands ange om 0.5 o 5 me e s, wi h
salini y le els a ying be ween 1 and 10 g/L. In he 1980–1999 pe iod,
g oundwa e le els luc ua ed be ween 180 and 210 cm, bu du ing he low-wa e
yea s o 2000–2001, hey deepened o 350–360 cm, sligh ly imp o ing soil
eclama ion s a us. App oxima ely 440,000 ha o i iga ed lands a e a ec ed by
g oundwa e salini y be ween 1–3 g/L, while mo e han 6,000 ha exceed 5 g/L.
Pe sis en seconda y saliniza ion is associa ed wi h shallow g oundwa e , low
na u al d ainage, and high e apo anspi a ion, con i ming ea lie hyd ogeological
indings (FAO, 2018; Ka imo e al., 2019).
3.4 The Cu en S a e o he A al Sea
The A al Sea con inues o sh ink. By 1990, i s o al a ea dec eased o 43,000
km², and he La ge A al became di ided in o eas e n and wes e n lobes. Today, he
eas e n pa has almos d ied ou , exposing o e 6 million hec a es o saline dese
su ace (O olqum). Annual windbo ne dus emissions om he desicca ed seabed
a e es ima ed a 75 million ons (UNEP, 2020). Moni o ing o he Sa bas, Moynaq,
and Shigekul wa e bodies shows mine aliza ion anging om 7 o 17 g/L, wi h
SO₄²⁻ and Cl⁻ dominance. This ex eme salini y unde sco es he impo ance o
eusing collec o -d ainage wa e s o sal - ole an c op i iga ion and a o es a ion
o he d ied seabed o mi iga e dus s o ms and ecological deg ada ion.
4. Conclusions
The hyd oecological condi ion o Ka akalpaks an’s wa e sys ems is c i ically
in luenced by an h opogenic wa e egula ion, insu icien d ainage, and long- e m
i iga ion p ac ices. The e ined landscape–halo-geochemical me hod p o ides a
obus amewo k o assessing hyd oecological s a us ac oss adminis a i e
dis ic s.
Implemen ing his me hodology in egional wa e managemen has enhanced
he accu acy o wa e accoun ing and quali y moni o ing (Ka akalpaks an Minis y
o Wa e Resou ces, 2020). Reuse o collec o -d ainage wa e s in saline lands
o e s a p ac ical adap a ion measu e in wa e -sca ce yea s, imp o ing eclama ion
e iciency and main aining ag icul u al p oduc i i y. Con inued moni o ing and
in eg a ion o GIS-based models a e essen ial o o ecas g oundwa e salini y
dynamics and o plan sus ainable wa e esou ce use in he A al Sea basin.
Acknowledgmen .
This s udy was ca ied ou wi hin he amewo k o he p ojec FL-8323102111-R1
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i led “De eloping a scien i ic basis o classi ying he plan ing a eas acco ding o
he salini y le el and he physical, chemical, and biological p ope ies o soil and
g ound ma e ials dis ibu ed in he d ied bo om o he A al Sea.”
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