Within the Sierra Norte de Madrid we have numerous streams and rivers that keep a wealth of botanical and fauna, In addition to its scenic value. Within these we would highlight the Lozoya and Jarama rivers basins, declared ZEC (Special conservation area), within the nature network 2000.

The runway of the Lozoya River is interrupted by five interconnected reservoirs (Pinilla, Riosequillo, Old bridges, Del Villar and the Atazar), reservoirs containing a wealth of ornithological, and where you can practise different activities, such as canoeing and paddle surf. The Sierra Norte was declared marine resort, and the Atazar reservoir hosts nautical facilities for various sports such as sailing.