International Journal of Aquaculture, 2026, Vol.16, No.2, 90-110 http://www.aquapublisher.com/index.php/ija 101 Table 2 Fit statistics of simulated data by WEAP and observed stream flow data for validation Fit Statistic Range Acceptable Range Value Mean Observed Flow (m³/s) 9.111 Mean Simulated Flow (m³/s) 8.621 Median Observed Flow (m³/s) 9.010 Median Simulated Flow (m³/s) 8.345 Standard Deviation (Observed) (m³/s) 4.786 Standard Deviation (Simulated) (m³/s) 3.767 Mean Absolute Error (MAE) (m³/s) 0 to ∞ Lower is better 5.886 Root Mean Square Error (RMSE) (m³/s) 0 to ∞ Lower is better 11.991 Nash-Sutcliffe Efficiency (NSE) —∞ to 1 > 0.5 0.807 Index of Agreement (IA) 0 to 1 Closer to 1 0.819 Coefficient of Determination (R²) 0 to 1 > 0.6 0.821 Source: Researcher (2025) 4.3 Scenario analysis and projected water demand (2022-2052) 4.3.1 Sectorial trends in water demand Domestic water use follows a gradual upward trajectory, driven primarily by population growth. Demand increases from 11.6 × 106 m³ annual in 2022 to nearly 36.8 × 106 m³ annual by the year 2052, necessitating infrastructure upgrades. Industrial demand use, though Higher than domestic demand is expected to rise steadily, increasing from 14.9 × 106 m³ annual in 2022 to 30.2 × 106 m³ annual by the year 2052. The table below summarizes the projection of the demands from base flow year to projected year 2052 (Table 3). Table 3 Overrow base year demand 2022 and projected year 2052 SUMMARY OF WATER DEMAND PROJECTION No. Supplied demand 2019 Base year 2022 2032 2052 1 Domestic Water Demand 11,039,060 11,648,610 16,753,865 36,871,205 2 Commercial Demand 7,212,035 7,653,320 8,791,390 3,063,350 3 Agricultural Demand 7,943,860 8,430,040 9,683,450 14,389,395 4 School Demand 5,818,100 6,173,975 7,091,950 10,538,280 5 Health Facility Demand 2,813,055 2,968,180 3,590,140 5,993,665 6 Industrial Demand 14,162,000 14,943,465 18,074,070 30,175,280 TOTAL WATER DEMAND 48,988,110 51,817,955 63,985,230 111,031,175 Total water demand across all sectors is projected to 111 × 106 m³ annual, underscoring the importance of sustainable practices such as rainwater harvesting, wastewater recycling, and efficient irrigation. Policy actions must focus on seasonal conservation, infrastructure resilience, and equitable distribution to meet growing demand. 4.3.2 Comparison with 2022 baseline water demand The 2022 baseline water demand under the current accounts scenario serves as a reference for assessing sectoral changes and planning needs. Total annual demand in 2022 was approximately 51.8 × 106 m³ annual. Industrial use accounted for the largest share (14.9 × 106 m³ annual) around 29%), followed by domestic (11.6 × 106 m³ annual) agriculture (28.4 × 106 m³ annual), commercial (7.6 × 106 m³ annual), school (6.2 × 106 m³ annual), and health sectors (2.9 × 106 m³ annual) (Figure 6). Two datasets are compared were: Base year (blue color); Projected year (orange color) The figure above compares total water demand from the 2022 baseline to projections for 2052. Demand is expected to rise from 51.8 × 106 m³ annual in 2022 to over 111 × 106 m³ annual in 2052 with a 53% demand increment. This is driven by population growth, urbanization, agricultural expansion, and industrial development. These trends highlight the need for adaptive management strategies, including wastewater recycling, rainwater harvesting, and improvements in irrigation and industrial efficiency. Infrastructure investment and policy interventions are essential to ensure sustainable water allocation.
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