They are greatly intersected by gullies or dry watercourses. There are permanent rivers and streams as well as many seasonal watercourses. No permanent watercourses and reservoirs are nearby. Ingress of water underground resulted in formation of subterranean watercourses and lakes. Other important watercourses are the Hamble, Meon, Beaulieu and Lymington rivers. The headwaters of three watercourses in the Lake Erie basin are in Geauga County. Locations close to watercourses and edges of ponds are preferred. The water is then suitable for irrigation, groundwater recharge, or release to natural watercourses. The grasslands on the edges of the watercourses, are heavily grazed. Aqueducts must span a crossing at the same level as the watercourses on each end. All villages are located near watercourses and fields. This process caused the river system in the Shire to flow in steeper watercourses. Watermills impact the river dynamics of the watercourses where they are installed. Most of these watercourses run in the mountainous regions. All these watercourses flow into Lake Rapel.