Water quality is essential for drinking, agricultural and industrial purposes, and sustainable water management. The Gharasou sub-basin is the primary water supply resource for the Karkheh River Basin (KRB), the third-largest and most productive river basin of Iran. This paper addressed the published papers about the water quality assessment of the Gharasou River. For this purpose, natural or anthropogenic pollution sources, land cover/land use, and soil erosion/runoff were considered. Water pollution indices, such as water quality index (WQI) and trophic diatom index (TDI), were also investigated. The suitability of the Gharasou River water for irrigation purposes was also studied. The results indicated that drought, weathering of bed sediments, and cation-exchange processes in the soil–water interface are natural sources of water pollution of the Gharasou River. A large-scale release of raw sewage and industrial chemicals, the geological texture, agricultural activities, and vehicles are anthropogenic sources of water pollution. WQI ranges from 33 ± 3 to 76 ± 6, and TDI ranges from 39.2 ± 5 to 71.3 ± 15, reflecting a significant level of pollution in the Gharasou River. USSL and FAO methods classified water as C₂S₁ (medium-salinity and low-sodium hazards). However, water quality indices indicated that there is a regional sodicity problem evidenced by a high risk for permeability index (PI) > 75%, Ca²⁺/Mg²⁺ ratio < 1, and magnesium ratio (MR) > 50 as well as nutritional and irrigation problems. Converting rangelands to rain-fed lands, overgrazing, and deforesting hilly land are the main factors affecting soil erosion/runoff, which consequently impacted the water quality of the Gharasou River.

水质对于饮用水、农业和工业用途以及可持续水资源管理至关重要。Gharasou 子流域是 Karkheh 流域 (KRB) 的主要供水资源，该流域是伊朗第三大和生产力最高的流域。本文针对已发表的关于加拉苏河水质评估的论文。为此，考虑了自然或人为污染源、土地覆盖/土地利用和土壤侵蚀/径流。还研究了水污染指数，如水质指数（WQI）和营养硅藻指数（TDI）。还研究了 Gharasou 河水是否适合灌溉。结果表明，干旱、床层沉积物风化、土壤-水界面中的阳离子交换过程和阳离子交换过程是加拉苏河水污染的天然来源。未经处理的污水和工业化学品的大规模排放、地质结构、农业活动和车辆是水污染的人为来源。WQI 范围为 33±3 至 76±6，TDI 范围为 39.2±5 至 71.3±15，反映了加拉苏河的严重污染水平。USSL 和 FAO 方法将水归类为 C₂ S ₁（中等盐度和低钠危害）。然而，水质指标表明存在区域碱度问题，渗透率指数 (PI) > 75%、Ca ²⁺ /Mg ²⁺比值 < 1 和镁比 (MR) > 50的高风险以及营养和灌溉问题。将牧场转变为雨养地、过度放牧和砍伐丘陵地是影响水土流失/径流的主要因素，从而影响了加拉苏河的水质。