Avoiding other plants to take root, in particular ones with deep roots as they would form weak points in the dense felt-like root system grass has. Also ease of inspection.
There’s about a millennium of engineering experience in those dikes… and plenty of historical compromises. Like, we knew back in the middle ages that flat profiles secured by grass are the most stable and secure but they require massive amounts of material so it was necessary to use inferior dikes with vertical faces made of wood planks. Most recent notable innovation is sand cores and ditches behind the dike to manage seepage water (behind meaning on the land side, always confuses them tourists), and some minor alterations to geometry to improve the way waves hit it.
We probably knew that sheep were good for dikes before we built them as, at least in principle, dikes are nothing but a warft with a hole in the middle and we’ve built those since time immemorial.
And in case you’re wondering yes we’re raising them quite a bit higher in anticipation of sea levels rising. Completely uncontroversial decision, only question was whether to rise the dikes very high, or use the same budget to raise them not as high, but wider, so that they can easily be made even very higher in the future. We went with the latter option, which is kinda optimistic and pessimistic at the same time.
Looks cool.
I really like it when people solve complex tasks with simple and natural means.
Same goes for analog electronics and 60s-80s ideas of the future of technology.
Only about keeping the grass short - why? Is it for the ground to dry faster?
Avoiding other plants to take root, in particular ones with deep roots as they would form weak points in the dense felt-like root system grass has. Also ease of inspection.
There’s about a millennium of engineering experience in those dikes… and plenty of historical compromises. Like, we knew back in the middle ages that flat profiles secured by grass are the most stable and secure but they require massive amounts of material so it was necessary to use inferior dikes with vertical faces made of wood planks. Most recent notable innovation is sand cores and ditches behind the dike to manage seepage water (behind meaning on the land side, always confuses them tourists), and some minor alterations to geometry to improve the way waves hit it.
We probably knew that sheep were good for dikes before we built them as, at least in principle, dikes are nothing but a warft with a hole in the middle and we’ve built those since time immemorial.
And in case you’re wondering yes we’re raising them quite a bit higher in anticipation of sea levels rising. Completely uncontroversial decision, only question was whether to rise the dikes very high, or use the same budget to raise them not as high, but wider, so that they can easily be made even very higher in the future. We went with the latter option, which is kinda optimistic and pessimistic at the same time.