Solutions to the global water shortages by damming the Baltic Ocean and the White Sea

Question

Geopolitics and costs aside, would damming the Baltic Ocean and the White Sea be enough to provide a renewable supply of water to water stressed Central Asia? Central Asia because its closest and has the Caspian Sea and Aral Sea which naturally provides a storage mechanism for the water.

I was thinking that if we dam the Baltic at Denmark, then over time the fresh water inflow in the north by means of rivers and freezing in winter (of 660 km³ annually) will completely replace the salt water in the ocean within a max time of 50 years (giving a little leeway for mishaps in between). Repeat the same for the White. This water can then be pumped to Aral or Caspian Sea by connecting it to the Volga river in Russia which drains into the Caspian. And then pump it into the Aral for more storage if necessary.

1 Billion people consume 500 km³ of water. Currently, the population of Central Asia is approximately 70 million. Assuming we the central Asian population will peak at 1 billion, then we have more than enough water. However this doesn't take into account Baltic ocean states water uses as they too will want some. The White Sea is also another source in the background using the same strategy of damming at the straits narrow point. So, will it work?

Answer 1

If you're only asking "would there be enough water replaced for both the Baltic Sea region and Central Asia", the answer is simple mathematics.

HELCOM states the size of the Baltic Sea catchment area to be some 1.74 million sq km (p. 10) and the mean precipitation since the mid-80s to be about 750 mm/a (p. 15).

1 740 000 km² × 750 mm = 1.740 × 10¹² m² × 0.75 m = 1.305 × 10¹² m³ = 1305 km³ precipitation in the catchment area per year.

So yes, theoretically the fresh water "generated" within the Baltic Sea area would be enough to supply the area itself and Central Asia, too, going with the numbers you ballparked. I will omit pointing at the many things you'd have to consider.

Answer 2

There is no "Global" water shortage Water is a geopolitical issue, the biggest is clean water in 3rd world and any available water in more arid regions. The nations with the biggest water issues

• Middle East: Scarcity issues
• China: Water Quality
• India: Both, availability is also a problem... small/moderate scale programs to address water issues, India leads the charge...on small village scale water acquisition, sterilization and well recharge.

Nuclear powered desalination offers the biggest grand scale changes for some nations, however technology is not applicable to poorer nations or nations whose Large scale water issues are byproduct of being in interior of continents away from ocean. Even if.... sending water hundreds or thousands of miles to water stressed regions (Often at high altitude regions) is a particularly expensive scenario. However there are some shorter term methods.

• Rainwater harvesting An inch of water over an acre of land produces 27,000 gallons of water. So 1000 square foot roof collects 623 gallons per inch of rainfall.
• Well pit recharge
• Flood based recharging pits like above
• Desalination Co-ops (Agree to cover partial cost of plant construction/operation in exchange for percentage of water)
• Harvesting agricultural runoff
• Re-forestation programs.
• microcatchment . (Landscaping features) The name Zai pits refers to small pits are dug in which seed of annual or perennial crops are planted. The pits They are beneficial for soil because they increase insect and worm activity which in turn leads to a higher water infiltration when it rains, these pits are fertilized with manure (Human or animal) which also stores water better than sandy/clay soils. This intervention is most suitable for flat or gently sloped terrains (0-5% gradient) with a precipitation quantity of 350-600 mm. Other designs like contour bunds, Negarim and other features catch water instead of letting it runoff and allow to infiltrate into the soil.

Dryer lands receive much more rain than we assume. The Netherlands, for example get's an average of 650mm (25.6 inches) of rainfall per year. Where as Xeric region Monterrey, Mexico has 680mm (26.8 inches) of rainfall. So How can the Netherlands despite having less rain, but have more fertile soils (besides a cooler climate) Be it degraded farmland or some xeric regions. Rainfall in some areas is Seasonal....in water stressed areas; water falls only at a peak of the year often a few weeks. Some regions have dry/wet seasons with six months of rain. Terrain: rain falls on slopes, hills and mountains and then flows out into streams and rivers that convey its runoff water into the sea. When areas are degraded or severely eroded, there is often a soil hardpan due to decades of compaction. The downside to no-till farming is that while it prevents soil erosion; it makes soil less permeable so only 15-25% of the water enters into the soil. The rest runs away. Pre-Industrial farmers built land terraces and planted hills, modern farming eschews that. Newly built landscaping terraces collect 3x the water to infiltrate the soil.