Using integrated GIS and hydrological analysis for sizing culverts of multiple channel crossings at the flooded section of the Daboya-Mankarigu Road (IR10) in Ghana.

A culvert is an important structure in Road construction to allow the conveyance of Channels crossing the road. Culverts are sized for a road to accommodate the volume of water crossing the road network to avoid flooding. Ghana Highways has a standard manual for culvert sizing at channel crossing. This manual serves as a guide for the proper sizing of culverts, however, lots of culverts have been found to have failed. Among the reasons for the failure of culverts could be under-sizing, urbanization, climate change, lack of maintenance, etc. The Daboya-Mankarigu Road is situated in the Savanah Region of Ghana in the North Gonja District. The section of the road from Chainage 9 + 075 to 10 + 200 has been experiencing flooding from 2020 to 2021 with a flood depth of 3.315 m in 2020 and 2.00 m in 2021. This study seeks to use integrated GIS and hydrological-based methods to propose new culverts to supplement the existing culverts to control flooding at section (9 + 075 to 10 + 200) of Daboya-Mankarigu Road (IR10). Geographic Information system (GIS) model (SWAT), Hydrological and hydraulic models were used to determine the peak flow at the catchment to Propose new culverts to supplement the existing culverts. Using a design period of 25 years for culverts, the modified rational method was used to determine the Peak flow of the catchment. A 25-year peak flow of 367.155 m3/s was determined and used for hydraulic analysis of the existing culverts. From the study, the existing culvert structures at the section had a hydraulic capacity of 78.732 m3/s which could not accommodate the remaining flow of 288.423 m3/s in the catchment. An observation was made that the changes in the rainfall can cause a change in rainfall intensity. An increase in built-up areas in the catchment can also increase the runoff coefficient which can result in higher peak flow in the catchment. Climate change, change in slope, and Land use in the catchment were also determined to have a huge influence on the adequacy of culverts since the peak flow is dependent on these parameters in the catchment as the years go by. A 4No. 4 m × 4 m box culvert, 3No. 3.5 m × 3.5 m box culvert, and 13 No. 1200 mm pipe culverts with 2 each at different chainages were proposed at suitable locations to supplement the existing culverts using the HDS-5 equations in AutoCAD Civil 3D. A recommendation is made to consider the installation of these new culverts at the flood section to control flooding and avoid overtopping of water on the IR10 road section (Daboya-Mankarigu) in the north Gonja District.

A quantitative global review of species population monitoring.

Species monitoring, defined here as the repeated, systematic collection of data to detect long-term changes in the populations of wild species, is a vital component of conservation practice and policy. We created a database of nearly 1200 schemes, ranging in start date from 1800 to 2018, to review spatial, temporal, taxonomic, and methodological patterns in global species monitoring. We identified monitoring schemes through standardized web searches, an online survey of stakeholders, in-depth national searches in a sample of countries, and a review of global biodiversity databases. We estimated the total global number of monitoring schemes operating at 3300-15,000. Since 2000, there has been a sharp increase in the number of new schemes being initiated in lower- and middle-income countries and in megadiverse countries, but a decrease in high-income countries. The total number of monitoring schemes in a country and its per capita gross domestic product were strongly, positively correlated. Schemes that were active in 2018 had been running for an average of 21 years in high-income countries, compared with 13 years in middle-income countries and 10 years in low-income countries. In high-income countries, over one-half of monitoring schemes received government funding, but this was less than one-quarter in low-income countries. Data collection was undertaken partly or wholly by volunteers in 37% of schemes, and such schemes covered significantly more sites and species than those undertaken by professionals alone. Birds were by far the most widely monitored taxonomic group, accounting for around half of all schemes, but this bias declined over time. Monitoring in most taxonomic groups remains sparse and uncoordinated, and most of the data generated are elusive and unlikely to feed into wider biodiversity conservation processes. These shortcomings could be addressed by, for example, creating an open global meta-database of biodiversity monitoring schemes and enhancing capacity for species monitoring in countries with high biodiversity. Article impact statement: Species population monitoring for conservation purposes remains strongly biased toward a few vertebrate taxa in wealthier countries.

Una Revisión Global Cuantitativa del Monitoreo Poblacional de Especies Resumen El monitoreo de especies, definido aquí como la recolección sistemática y repetida de datos para detectar cambios a largo plazo en las poblaciones de las especies silvestres, es un componente vital de la práctica y las políticas de la conservación. Generamos una base de datos de casi 1,200 esquemas, con un rango de fecha de inicio desde 1800 hasta 2018, para revisar los patrones espaciales, temporales, taxonómicos y metodológicos en el monitoreo global de especies. Identificamos los esquemas de monitoreo por medio de búsquedas estandarizadas en línea, una encuesta digital realizada a los actores, búsquedas a profundidad en una muestra de países y en una revisión global de las bases de datos sobre la biodiversidad. Estimamos el número total mundial de esquemas funcionales de monitoreo entre 3,300 y 15,000. Desde el 2000, ha habido un fuerte aumento en el número de esquemas nuevos que han iniciado en países de bajo o mediano ingreso y en países megadiversos, pero una disminución en los países de alto ingreso. El número total de esquemas de monitoreo en un país y su producto interno bruto per cápita tuvieron una correlación sólida y positiva. Los esquemas que estaban activos en 2018 lo habían estado en un promedio de 21 años en los países de alto ingreso, comparado con un promedio de 13 años en los países de mediano ingreso y de 10 años en los países de bajo ingreso. En los países de alto ingreso, más de la mitad de los esquemas de monitoreo recibieron financiamiento del gobierno, comparado con menos de un cuarto de los esquemas en los países de bajo ingreso. La recolección de datos se realizó parcial o totalmente por voluntarios en 37% de los esquemas, y dichos esquemas cubrieron significativamente más sitios y especies que aquellos realizados sólo por profesionales. Las aves fueron por mucho el grupo taxonómico más monitoreado, comprendiendo casi la mitad de todos los esquemas, pero este sesgo declinó con el tiempo. El monitoreo en la mayoría de los grupos taxonómicos todavía es disperso y descoordinado, y la mayoría de los datos generados son vagos y tienen poca probabilidad de alimentar procesos más amplios de conservación de biodiversidad. Estas deficiencias podrían abordarse, por ejemplo, creando una meta-base de datos globales abiertos de los esquemas de monitoreo de la biodiversidad y mejorando la capacidad para el monitoreo de especies en los países con alta biodiversidad.