Discover and read the best of Twitter Threads about #TodaysHappiness
Most recents (1)
#TodaysHappiness c175BC #IronAge communities along the Rhine estuary nor Rotterdam minimised the flow of salt water onto their coastal grazing in a system that was maintained for at least 350 years... 
2. They built retaining banks with dams behind them to store fresh water flowing to the coast during high tides. At low tides, that water drained into the sea through timber pipes. As the sea water rose during high tides, it pushed against clappers on the pipes' seaward ends ....
3. closing the pipes to protect the grazing: salt water was prevented from coming in & water flowed only towards the sea.
