Las Madres lake GEOGRAPHIC LOCATION: Jarama river catchment, Arganda del Rey town council. The site is located on the right side of M-3020 road, km 1.8. ALTITUDE: 530 m.a.s.l. COORDINATES (LAT. and LONG.): 40º 18’ 10’’ N, 3º 31’ 10’’ W Main biotic community: planktonic