Assessing the Relationship Between Electrical Conductivity and Total Dissolved Solids of Different Water Resources in a Large-scale Irrigation Scheme in the Eastern Mediterranean Basin of Turkiye

Year 2024, Volume: 39 Issue: 2, 254 - 266, 30.12.2024

Mahmut Çetin , Omar Alsenjar , Angela Hiuhu , Muhammet Said Gölpınar , Müge Erkan Can

Abstract

Climate change and the growth of the population have led to changes in both the quantity and the quality of water resources. In Turkiye, a Mediterranean country, over 75% of its surface water is used for irrigation. Given the average annual precipitation (574 mm) of Turkiye, except for the Black Sea Region, all arable land in the country relies on irrigation to maintain sustainable food production. Agriculture constitutes 6% of Turkiye’s gross domestic product (GDP), with exports including crops such as cotton, corn, cereals, pulses, oilseeds, nuts, citrus orchards, and various fruits. As a result, the water provided for irrigation in any irrigation system must meet acceptable water quality standards to ensure sustainability of irrigation and food security. This study aims to a) investigate two essential irrigation water parameters: Electrical Conductivity (EC) and Total Dissolved Solids (TDS), and b) evaluate their empirical relationship using samples collected from various water sources within a large-scale irrigation district, covering an area of 9495 ha in the Eastern Mediterranean Region of Turkiye. Water samples were collected over one year, from October 2022 to September 2023. A total of thirteen locations were considered: a) Seven agricultural drainage channels, b) Four irrigation water sources (Seyhan River, Ceyhan River, one spring, and one groundwater well), c) Two outlets - the existing research catchment outlet and the other downstream. EC values of water samples were determined by using a benchtop type EC meter in the laboratory and TDS was determined by gravimetric method. Research results showed that there was a statistically significant correlation (r≥0.98) between EC and TDS across all water samples. The proportionality constant (K) ranged predominantly between 400-800 and was consistent with literature indicating the linear relationship between EC and TDS. Research findings suggest that the quality of different water supplies is suitable for the irrigation of all kinds of crops grown in the Lower Seyhan Plain of Turkiye. The overall characteristics of the average EC and TDS values throughout the year are reflected in the proposed equations for each water body. However, in future research, we suggest that the water sample volume should be at least 100 ml in order to provide more accurate results for water quality assessment.

Keywords

Electrical conductivity (EC), total dissolved solids (TDS), water quality, irrigation catchment scale, Lower Seyhan Plain (LSP)

Ethical Statement

The authors declare no conflicts of interest

Supporting Institution

Scientific Research Projects (BAP) Coordination Unit of Cukurova University

Project Number

FDK-2022-1490

Thanks

The authors thank the Scientific Research Projects (BAP) Coordination Unit of Cukurova University for funding this research [Project Number: FDK-2022-14907]. The author, Angela Hiuhu, would like to thank the authorities of the University of Cukurova and the University of Nairobi for allowing her to be in Turkiye as part of the Erasmus Plus mobility program.

Türkiye'nin Doğu Akdeniz Havzasındaki Büyük Ölçekli Bir Sulama Şebekesinde Farklı Su Kaynaklarının Elektriksel İletkenliği ve Toplam Çözünmüş Katı Madde Arasındaki İlişkinin Değerlendirilmesi

Abstract

İklim değişikliği ve nüfus artışı, suyun hem miktarında hem de kalitesinde değişikliklere neden olmaktadır. Bir Akdeniz ülkesi olan Türkiye’de, yüzey sularının %75’ten fazlası sulama amacıyla kullanılmaktadır. Yıllık ortalama 574 mm yağış düşmesine rağmen, Karadeniz Bölgesi hariç olmak üzere, Türkiyedeki tarıma elverişli tüm arazilerde, sürdürülebilir tarımsal faaliyetler ve gıda güvenliği sulamaya bağlıdır. Tarım, Türkiye'nin gayri safi yurtiçi hasılasının (GSYİH) %6'sını oluşturmakta olup, ihracat ürünleri arasında pamuk, mısır, tahıllar, baklagiller, yağlı tohumlar, fındık, narenciye bahçeleri ve çeşitli meyveler bulunmaktadır. Dolayısıyla, gıda güvenliğini sağlamak için, sulamada kullanıulan suyun, kabul edilebilir kalite standartlarını karşılaması gerekmektedir. Bu çalışmanın amacı: a) İki temel sulama suyu parametresini analiz edip, irdelemek: Elektriksel İletkenlik (EC) ve Toplam Çözünmüş Katı Madde (TDS) ve b) Türkiye'nin Doğu Akdeniz Bölgesi'nde 9495 hektarlık bir alanı kapsayan büyük ölçekli bir sulama bölgesindeki çeşitli su kaynaklarından toplanan örnekleri kullanarak EC ve TDS arasındaki ampirik ilişkileri elde ederek değerlendirmektir. Analiz edilen su örnekleri, Ekim 2022 ile Eylül 2023 tarihleri arasında bir yıllık bir dönem boyunca toplanmıştır. Araştırmada, toplam 13 farklı konumdan alınan su öneklerinin kalitesi dikakte alınmıştır: a) Yedi tarımsal drenaj kanalı, b) Dört sulama suyu kaynağı (Seyhan Nehri, Ceyhan Nehri, bir kaynak/pınar suyu ve bir yeraltı suyu kuyusu), c) İki drenaj çıkış noktası -mevcut araştırma havzası çıkışı ve bu çıkıştan daha mansapta yer alan bir lokasyon. Su örneklerinin EC değerleri laboratuvarda EC metre kullanılarak, TDS değerleri ise gravimetrik yöntemle belirlenmiştir. Tüm su örnekleri için, EC ve TDS değerleri arasında istatsitiksel anlamda önemli bir korelasyon (r≥0.98)) bulunmuştur. EC ve TDS asasındaki doğrusla ilşkiyi gösteren orantı sabiti (K) genellikle 400-800 arasında değişmiştir. Bu değerlerin, EC ve TDS arasındaki doğrusal ilişkiyi gösteren literatürle tutarlı olduğu tespit edilmiştir. Araştırma bulguları, Türkiye'nin Aşağı Seyhan Ovası'nda su kalitesinin, yörede yetiştirilen bitkilerin sulanmasına uygun olduğuna iaşret etmiştir. Her su örnekleme noktası için belirlenen deneysel ilişki denklemleri, yıl boyunca ortalama EC ve TDS değerlerinin genel özelliklerini yansıtmıştır. Bununla birlikte, gelecekte yapılacak olan araştırmalarda, su kalitesi değerlendirmelerinde daha doğru sonuçlar elde etmek için, su örneklem hacimlerinin en az 100 ml olması önerilmiştir.

Keywords

Elektriksel iletkenlik (EC), toplam çözünmüş katı madde (TDS), su kalitesi, sulama şebekesi ölçeği, Aşağı Seyhan Ovası (ASO)

Ethical Statement

The authors declare no conflicts of interest

Project Number

FDK-2022-1490

Thanks

The authors thank the Scientific Research Projects (BAP) Coordination Unit of Cukurova University for funding this research [Project Number: FDK-2022-14907]. The author, Angela Hiuhu, would like to thank the authorities of the University of Cukurova and the University of Nairobi for allowing her to be in Turkiye as part of the Erasmus Plus mobility program.

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