This paper proposes an efficient sensor deployment model, called 'MOdel Driven GRAdient Deployment for Irregular Terrain' (MoDGraDIT), for increasing network lifetime and data gathering accuracy. MoDGraDIT uses two steps for computing the sensor deployment density. First, the number of children for any intermediate node has been estimated based on the connected-coverage criteria. Second, sensors are deployed in high redundancy to sustain node failures. The density of deployment has been estimated that depends on the computed 'Energy Dissipation Factor' (EDF), considering the gradient effect of energy depletion. The performance of MoDGraDIT has been analyzed using theoretical and simulation results. © 2016 Elsevier Ltd. All rights reserved.