This work addresses the problem of extending the lifetime of a wireless sensor network, when a bounded delay on receiving the packets is acceptable for a given sink node. The temporal threshold for the Quality of Data (QoD) tolerance is specified with respect to the time that it takes for the packets to travel from the source to the sink along an optimal route. For these settings, we propose a methodology that enables controlling the spatio-temporal load balancing among the sensors around the optimal route. Given the QoD threshold, we use it to derive a set of parameterized Bezier curves which serve as alternate routes between the (source,sink) pair, relieving the nodes along the optimal route, while ensuring a bound on the delay of packets delivery. We provide experimental results which demonstrate that our proposed methodology can prolong the sensor networks? lifetime for various definitions of the concept of a "lifetime" in the existing literature.