Addressing the challenges posed by climate change requires a multifaceted approach encompassing both adaptation and mitigation strategies. This chapter advocates for the recognition and application of “natural climate solutions” as a key component in this effort. Additionally, naturally occurring isotope techniques, as a zero-emission clean energy source, offer potential contributions to sustainable energy practices. Furthermore, the recycling and reprocessing of naturally occurring isotopic waste present viable options for minimizing environmental impact. The present work focuses on the application of naturally occurring isotopes, specifically water isotopes (18O,2H,3H), in tackling hydrological issues encountered in water resources assessment. Utilizing these isotopes provides a comprehensive understanding of various aspects such as delineating aquifer and basin system boundaries, determining the origin (genesis) of water, establishing hydraulic connections with surface water, and addressing multi-aquifer systems. The primary objective of the study is to dissect hydrographs into their constituent elements by employing naturally occurring tracers. By doing so, the research aims to contribute to sustainable water resources management and, simultaneously, reduce greenhouse-gas emissions on a global scale. The differentiation between pre-event water, often termed “old water,” and event water, referred to as “new water,” is crucial in understanding the dynamics of stormflow origins and their distinct chemical and isotopic signatures. In conclusion, the integration of natural climate solutions and naturally occurring isotope techniques emerges as a promising approach for achieving sustainable water resources management. The findings of this research contribute valuable insights to the broader discourse on climate change adaptation and mitigation, emphasizing the importance of interdisciplinary strategies in addressing complex environmental challenges.