Law and legislation 549 National parks and reserves 115 Land titles 114 Registration and transfer 114 Historic sites 87 Boundaries 75 Water resources development 45 más ... Finance 31 Cultural property 29 Protection 29 Hydroelectric power plants 28 Research 26 Trails 26 Real property, Exchange of 25 Wild and scenic rivers 25 Wilderness areas 23 Public lands 22 Appropriations and expenditures 20 Water reuse 19 Forest reserves 17 Monuments 17 Memorials 16 Watershed management 15 Recreation areas 14 Eau 13 Energy conservation 13 Groundwater 13 History 13 Biens réels 12 Design and construction 10 menos ...