The people of Cumbum and nearby villages played a vital role in the construction of Mullai Periyar Dam. When John Pennycuick decided to divert the west-flowing Periyar River eastward so that it could irrigate acres of dry land, the construction works were disrupted by relentless rain. Large numbers of sand bags kept for the construction of the dam were destroyed due to flooding. Since he could not get adequate funds from the British government, Pennycuick went to England and sold his property to raise the money. Local landowners in Cumbum and Gudalur provided more money, along with manpower, to aid in the dam's construction. It was completed in 1895.