Ð 3\/4 Ð Ð Ð Ð 1\/2 Ñ Ñ The Chernye Zemli Irrigation Scheme ( Ð Ð Ñ Ð 1\/2 Ð 3\/4 Ð Ð Ð 1\/4 Ð Ð '' Ñ Ñ Ð Ð Ñ Ð 3\/4 Ñ Ð 3\/4 Ñ Ð Ñ Ð Ð '' Ñ Ð 1\/2 Ð Ñ Ñ Ð Ñ Ñ Ð Ð 1\/4 Ð ) in southern Kalmykia receives water from the Caucasian rivers Terek and Kuma via a chain of canals : water flows from the Terek to the Kuma via the Terek-Kuma Canal , then to the Chogray Reservoir on the East Manych River via the Kuma-Manych Canal , and finally into Kalmykia 's steppes over the Chernye Zemli Main Canal , constructed in the 1970s .