sentence: the first of a series of gablestones on a gemeenlandshuis in halfweg built in 1645 ; each stone represents the heraldic shield of the dike-reeve and his men , known as the heemraden , or in this case , the high or hoogheemraden a dijkgraaf ( translated : dike-warden or dike-reeve ) , sometimes called a watergraaf , is the chair of a dutch water board .