Abstract：
A comprehensive seasonal assessment of groundwater vulnerability was conducted in the weathered hard rock aquifer of the upper Swarnrekha watershed in Ranchi district, India. Lineament density (Ld) and land use/land cover (LULC) were integrated into the conventional DRASTIC and Pesticide DRASTIC (P-DRASTIC) models and were extensively compared with six modified models, viz. DRASTIC-Ld, DRASTIC-Lu, DRASTIC-LdLu, P-DRASTIC-Ld, P-DRASTIC-Lu, and P-DRASTIC-LdLu, to identify the most optimal model for vulnerability mapping in hard rock terrain of the region. Findings were geochemically validated using NO3- concentrations of 68 wells during pre-monsoon (Pre-M) and post-monsoon (Post-M) 2022. Irrespective of the applied model, groundwater vulnerability shows significant seasonal variation, with > 45% of the region classified as high to very high vulnerability in the pre-M, increasing to ̴67% in post-M season, highlighting the importance of seasonal vulnerability assessments. Agriculture and industries\' dominant southern region showed higher vulnerability, followed by regions with high Ld and thin weathered zone. Incorporating Ld and LULC parameters into DRASTIC-LdLu and P-DRASTIC-LdLu models increases the \'Very High\' vulnerability zones to 17.4% and 17.6% for pre-M and 29.4% and 27.9% for post-M, respectively. Similarly, \'High\' vulnerable zones increase from 32.5% and 25% in pre-M to 33.8% and 35.3% in post-M for respective models. Model output comparisons suggest that modified DRASTIC-LdLu and P-DRASTIC-LdLu perform better, with accurate estimations of 83.8% and 89.7% for pre-M and post-M, respectively. However, results of geochemical validation suggest that among all the applied modified models, DRASTIC-LdLu performs best, with accurate estimations of 34.4% and 20.6% for pre-M and post-M, respectively.
摘要：
在兰契地区上斯瓦恩雷卡流域的风化硬岩含水层中，对地下水脆弱性进行了全面的季节性评估，印度。线密度（Ld）和土地利用/土地覆盖（LULC）被整合到传统的DRASTIC和农药DRASTIC（P-DRASTIC）模型中，并与六个修改的模型进行了广泛的比较，viz.DRASTIC-Ld,DRASTIC-Lu,Dratic-LdLu,P-DRASTIC-Ld,P-DRASTIC-Lu,和P-DRASTIC-LDLu,确定该地区硬岩地形脆弱性测绘的最优模型。在2022年季风前（Pre-M）和季风后（Post-M）期间，使用68口井的NO3-浓度对调查结果进行了地球化学验证。无论应用的模型如何，地下水脆弱性表现出显著的季节性变化，>45%的区域在前M被归类为高至非常高的脆弱性，在M后赛季增加到67%，强调季节性脆弱性评估的重要性。农业和工业占主导地位的南部地区表现出更高的脆弱性，其次是高Ld和薄风化带的区域。将Ld和LULC参数纳入DRASTIC-LdLu和P-DRASTIC-LdLu模型，将M前的“非常高”漏洞区域增加到17.4％和17.6％，将M后的29.4％和27.9％，分别。同样，对于各个型号，“高”易损区域从M前的32.5%和25%增加到M后的33.8%和35.3%。模型输出比较表明，修改后的DRASTIC-LDLu和P-DRASTIC-LDLu表现更好，前M和后M的准确估计为83.8%和89.7%，分别。然而,地球化学验证结果表明，在所有应用的修改模型中，DRASTIC-LDLU表现最好，前M和后M的准确估计为34.4%和20.6%，分别。
