Many academic books offer suggestions, specifically for Iran and to draw on the world's knowledge. One example is https://www.whpress.co.uk/publications/2012/03/30/changing-deserts/

There is no single solution that can solve the water crisis in large cities. A comprehensive and integrated approach is necessary. The water shortage stems from a combination of climate change, geographical challenges, and unsustainable water management practices.

Dangers of Groundwater Depletion: Draining groundwater is a dangerous and unsustainable practice. Over-extraction from aquifers leads to land subsidence, a severe problem in most cities around the globe where the ground sinks, damaging buildings and infrastructure. It also degrades water quality by increasing salinity and mineral concentration, making the water unsuitable for drinking.

Watershed Management: Watershed management in mountainous areas is a crucial and suitable method for cities near mountain ranges. Healthy, forested watersheds act as natural sponges, slowing rainfall and allowing it to infiltrate the soil. This process recharges underground aquifers and ensures a steady, high-quality flow of water. It also helps regulate water flow, mitigating both floods and droughts.

Some suitable solutions:

1. Hydrological and Watershed Management: Protecting and restoring natural ecosystems in upstream mountainous areas is fundamental. Practices like afforestation and erosion control can increase rainwater infiltration.

2. Water Conservation and Efficiency: This is the most immediate and impactful solution. It involves public awareness campaigns, using water-saving appliances, and repairing aging pipelines to reduce leakage.

3. Sewage Treatment and Water Recycling: Treating and reusing wastewater creates a new, non-potable water source for agricultural irrigation, industrial processes, and aquifer recharge.

4. Forest Vegetation and Artificial Lakes: Urban forests and green spaces can help regulate the microclimate and increase local water retention. Artificial lakes can capture and store surface water from rainfall.

A most interesting question and posts. If i may add another aspect to the discussion of water shortages to Tehran and sadly other cities in Iran, for example see Esfahan, is the economic side of matters. In rather brief and simplistic terms, water, for an economic perspective is not given its appropriate value, thus this does not result in appropriate water prices and costs. Clearly water is priced socially as water is a societal product, but this leads to, for example, over usage, waste and lack of intervention in water infrastructure. On the matter of water infrastructure, for example, pipes break, and leaks occur, there is little strict economic incentive to repair it as the loss of water in economic returns does not justify the intervention costs to fix it. What provides usually for intervention to fix broken water pipes are commonly social and political pressures, but such interventions commonly focus on 'patching up' and not on repairing or better still replacing aging water infrastructure. Further, there is also the fact of increasing urbanization in Iran, thus implying concentration and agglomeration of water supply as well as the demographic increase that has occurred over the past 40 years, which also implies greater supply of water as per the growing demand. However, water infrastructure for such urban agglomerations like Tehran and Isfahan, for example, were not designed, from a supply point of view as well as an economic point of view to cater for such changes that have occurred in such a short time period.