Early morning radio: a man is watching water climbing the stairs. It’s not the first time he’s been flooded out and it will happen again as arguments for dredging and speeding flow versus slowing the onrush – via water meadow and meander – flip-flops again. This is winter 2015/16, yet these arguments occur across Europe over centuries.
The Merwede broke its banks in 1658, 1709, 1726, 1728 and 1729. I know this because these dates appear next to the word ‘inbraken’ all along the north bank of Nicolaus Cruquius’s 1730 map.
He and a team of ‘experts’ were asked to explore means of flood prevention and his map forms part of the:
“Report of the professors s’ Gravesande and Wittichius, and of the land surveyor Cruquius relating to the inspection done of the river Merwede downstream from Gorinchem and relating to the proposed means to prevent inundations”
Cruquius needed to understand and make explicit the complex undulations of the river bed. Here I would like to add ‘thus he invented isobaths’, but of course lines marking depth had appeared on both manuscript and printed maps before. But he was the first to apply a system of bathymetric (submarine) contour lines to a printed map. He took over a year to chart the Merwede between Woudrichem and Hardinxveld. Using the low tide, he drove long stakes into the river-bed at right angles to the bank, creating a series of ‘spot depths’. These he interpolated (guesstimated) between to create lines along the course of the river at 5ft depth intervals.
In fact his coverage is so thorough; where space permitted he added extra dotted lines marking intervals as little as 1ft differences. These dotted lines begin and end abruptly, a curious sight for those used to following a contour’s sinuous curves, especially where he gently blends them with traditional ‘unmeasured’ hachuring towards the map edges .
So then, as now; for all the meticulous detailed mapping and thorough investigation, the hard won recommendations were shelved.