Morphometric analysis and the validity of Hortonian postulations in Anambra drainage basin, Nigeria Chinero Nneka Ayogu 1 • Philip Ogbonna Phil-Eze 1 • Nnadozie Onyekachi Ayogu 2 • Rapheal Iweanya Maduka 2 Received: 10 June 2018 / Revised: 4 February 2019 / Accepted: 7 February 2019 Ó Korean Spatial Information Society 2019 Abstract Anambra drainage basin is decimated by a ple- thora of rivers emanating from heavy rainfall and fluvio- geomorphic surface processes. Apparently, hydrologic and sedimentologic processes influences basin form and pro- cesses which are governed by laws of drainage basin composition postulated by Horton. Metrical dimension provides linearity, topographic and area variables used to validate Horton’s postulates in the Anambra drainage basin. Topographic tools and ARC GIS 10.2 were utilized. The stream number, length and areal quantities showed that the three laws of drainage basin composition postulated by Horton are valid. It is a 6th order dendritic pattern with elongated shape and coarse texture. The drainage density, stream frequency and infiltration number were with low values: 0.10, 0.10 and 0.27 respectively while the overland processes recorded 0.51, implying heavy dissection. The constant of channel maintenance is 0.99 km 2 . The relief characteristics indicated a low relief. The significance of the morphometric attributes of the Anambra drainage basin has a lot of implications in agricultural practice and erosion processes. Keywords Anambra drainage basin Á Morphometric parameters Á Stream order Á Relief Á Horton’s laws 1 Introduction Morphometric analysis focuses on the geo-spatial dimen- sions of a drainage basin. Foundation studies [1–5] revealed that it is important in deciphering basin form and processes together with their responses to internal and external factors prevailing in a drainage basin. Researchers have enunciated different definitions—measurement, quantification and measurement and quantifications aimed at configuring landforms [6, 7] and quantitative description of drainage basin which profoundly shape the watershed characteristics [4]. In affirmation to the above, [7, 8] cen- tralized that it facilitates the elucidation of earth surface processes and the configuration of a basin. Approvingly, [9] echoed that evolution and co-evolution of forms pro- vides insight about a watershed. Babu et al. [10] succinctly articulated the nexus between drainage networks’ attri- butes, climate, geology, relief and structural features. Thus, we define morphometric analysis as an evaluation of the spatial spread-cum-dimensions of a river basin landscape with precision which ultimately portrays the basin characteristics. Morphometric analysis of river basins unravels the metrical dimensions of earth surface ranging from shape and pattern, linear, areal and relief attributes. These are very vital for the maximum utilization of water resources and achieving sustainability. In other words, to avert the problems of unavailability of water despite the bourgeon- ing increase in human population and their demand for water, basin appraisal is very necessary [6, 11]. Laying our trust on extant literature review, we posit that morphometric analysis is among the sophisticated quantification researches carried out in geomorphology. This is because of the precision that can be established unlike [12] which anchored principally on qualitative & Chinero Nneka Ayogu chinero.ayogu@unn.edu.ng 1 Department of Geography, Faculty of Social Sciences, University of Nigeria, Nsukka, Nigeria 2 Department of Geology, Faculty of Physical Sciences, University of Nigeria, Nsukka, Nigeria 123 Spat. Inf. Res. https://doi.org/10.1007/s41324-019-00252-6