Over the past decade, solar photovoltaic installations have grown significantly, and energy storage is crucial for integration. Pumped storage hydropower is a cost-effective and proven grid-scale energy storage technology, reducing variable renewable energy curtailment. Floating solar photovoltaics can address water availability issues in arid regions by floating on water bodies. This research article explores a sustainable and cost-effective approach to enhancing water, energy, food, and ecosystem nexus in arid regions. It proposes a hybrid configuration of 200 MW Paras pumped storage hydropower, 30 MWp floating solar photovoltaic integrated with 300 MW Balakot conventional hydropower for grid energy storage. This study calculates the levelized cost of energy storage using conventional hydropower resources, water stream considerations, and floating solar PV installations. The novelty is that the levelized cost of energy storage decreases by 28 %, benefit to cost ratio increases by 56 % and installed costs are reduced by 25 % as compared to greenfield closed-loop pumped storage hydropower. The hybrid configuration can deliver an additional 3693 GWh of clean energy, resulting in a 30 % increase in revenue over 30 years compared to greenfield closed-loop pumped storage hydropower. This can improve the water, energy, food, and ecosystem nexus by enabling fast-track deployment of variable renewable energy in arid regions, while integrated pumped storage hydropower supports essential energy storage to the grid.