Mervyn Cowie oversaw the development of several of Kenya's national parks and designed them with human visitors in mind. This emphasis helped to make tourism Kenya's primary industry. However, it exacerbated problems between the human population and wildlife. Farmers living next to the parks did not have input into the establishment of the parks. Locals received very little benefit from the game animals. Livestock is threatened by lions, and some landowners think that Kenya's wildlife is not good for them. In 1948, 188,976 people lived in Nairobi, and by 1997 the city's population had grown to 1.5 million. The park is under pressure from the city's growing population and need for farmland. People live right next to the park's boundaries, which creates human-animal conflicts. The human population also creates pollution and garbage. Effluent and industrial waste from factories located along the park's northern boundary contaminate the park's surface and ground water systems.