This paper presents a data routing protocol for a non-mobile, locationaware wireless sensor network that is primarily designed for continuous monitoring application (e.g. environmental, infrastructure, under-water or agricultural monitoring). The protocol, in addition to optimally minimizing the total energy consumption of all sensors over all rounds of data gathering, also balances the load on them. The algorithm works in polynomial time complexity and is completely centralized. However, it incurs less overhead as the data routing information is disseminated to all sensors only once at the network initialization.