Problems of river bank and in-stream erosion are very common in most of the rivers in india and abroad. various attempts have been made to overcome excessive erosion by constructing river training works. porcupine systems are one of the novel techniques which have been adopted as a cost-effective method of river training. in this paper, the effect of porcupines on the velocity of flow and their ability to capture sediment has been investigated experimentally. also, an attempt has been made to logically study the pattern of deposition caused by various configurations of porcupine field layout and hence to propose a preliminary design methodology. results show that there is a considerable reduction in the flow velocity resulting in the deposition of sediment with porcupines offering resistance to flow. following indices have been developed in this study: pfdi (porcupine field density index) = length of one retard/spacing between two retards pfsi (porcupine field submergence index) = depth of water over porcupine/total depth of water bdf (bed deposit factor) = depth of sand deposited/depth of water pflf (porcupine field length factor) = length of one compartment of porcupine field/total length of compartments optimum values of these indices have been calculated experimentally for different flow rate and sediment concentration in any river. based on the experimental investigation carried out in the present research, following conclusions can be drawn: (1) presence of porcupines can cause considerable reduction in the flow velocity, which enhances further with increase in the number of units placed in a series. a second tier of porcupines can be placed over the other to improve their performance in the cases of high submergence. (2) densely configured porcupine field can capture more sediment than a sparse field. sediment capture capacity also increases with increase in sediment concentration of flow. (3) new suitable design indices have been developed in this study which could be used to form the basis for the preliminary design methodology and thus improve on the present day conjectural approach. (4) preliminary design template is developed which can provide the designer with the range of values of porcupine field density index for different sediment concentration and porcupine field submergence index, to achieve the desired objective of erosion control, moderate reclaim and heavy reclaim in the reach. proposed design has been verified with field applications at the brahmaputra river in assam.