The importance of adequate drainage for agricultural productivity is well known. In Old Regime France, drainage could have significantly increased agricultural output on two areas. First, in many regions of France, fields already under the plow would have greatly benefited from increased water control. Second, as we have seen in Chapter 4, drainage played a crucial role in bringing new land under production. Between 1700 and 1850, draining fields already under the plow presented a complex institutional problem because it required reallocating customary, common, and private property rights at once. In the case of marshes, the problem was more modest, since only customary and common rights had to be altered. This chapter focuses on the problems associated with draining marshes in a specific area: lower Normandy in northwestern France (see Map 1.1). The climate and geography of lower Normandy make it ideal for a study of drainage because it endures both steady rainfall and inadequate natural drainage over a large proportion of its terrain. More specifically, within lower Normandy the area most in need of drainage was the Dives Basin (Map 6.1). The basin had originally been almost all marsh, but in the Middle Ages abbeys had spearheaded settlement and drainage, yet in the eighteenth century, much land still remained poorly developed; these lands are the focus of our first detailed study of the interaction between institutions and drainage.

The Dives Basin lies on the coast of the English Channel in Normandy, only a few miles east of Caen in the department of the Calvados. It corresponds roughly to the present canton of Troarn and is a very flat plain with small hills.