Background: Exponential growth in population and over-exploitation has created groundwater stress situation in several regions globally. The peninsular area spread in the Bhagalpur and Khagaria districts of Bihar (India) is rich in groundwater, but decrease in groundwater level has been observed in the last decade. 
 
Methods: In this study, groundwater potential zones have been delineated using remote sensing and geographic information system (GIS) based AHP. The occurrence of groundwater in the study area is mainly affected by following factors- geomorphology, lithology, lineaments, drainage, soil, annual rainfall, slope, land use land cover and fluctuations in groundwater level. Above factors were considered as themes and were prioritized over each-other using the Analytic Hierarchy Process and merged in a GIS environment to delineate the groundwater potential zones. 
 
Result: Four different zones of groundwater potential- low, moderate, high and very high have been observed in the study area. The moderate and high groundwater potential zones cover 44% and 55%, respectively. The delineated potential zones have also been validated using the groundwater levels of the pre- and post-monsoon seasons, which match well. The areas at higher elevations were in the moderate potential zones.

Geographical Information System for Groundwater Potential Zoning in a Peninsular Region of Bihar

Background: The Burhi Gandak river origins in the Chautarwa Chaur region near Bisambharpur in the West Champaran district of Bihar and flows through the East Champaran, Muzafarpur, Samastipur and Begusarai districts. It falls into the river Ganga near Khagaria district. Its coordinates are 25&deg;51&#39;40&#39;&#39;N latitudes and 85&deg;48&#39;36&#39;&#39;E longitudes. The total area of catchment is 12500 sq. km in size overall, of which 9601 sq. km are in Bihar and the rest in Nepal. The study will be helpful for stock estimation, developing conservation and choosing appropriate species for aquaculture. The present data can be used to develop conservation plans while providing biological data needed for an effective management of this fishery. 
 
Methods: The carapace length-weight, carapace width-weight relationship, condition factor and sex ratio of freshwater crab Sartoriana spinigera (n=663) collected from River Burhi Gandak, North Bihar, between July 2020 to June 2021. In the present investigation, freshwater crabs were collected from different types of techniques, including hand-picking, digging, setting traps and taking them from their nest.&nbsp; 
 
Result: Total of 663 specimens of Sartoriana spinigera (Wood-Mason, 1971) of both sexes (male and female) were collected in which 363 female and 300 male. The carapace length-weight of Sartoriana spinigera females were calculated as W = 0.9122.521 with R2 = 0.875, male W = 0.43102.505 with R2 = 0.853 and length-weight of combined sex (male and female) were calculated as W = 0.6612.701 with R2 = 0.954. The carapace width-weight of female were calculated as W = 0.5542.331 with R2 = 0.831, male W = 0.7912.421 with R2 = 0.802 and carapace length-weight of combined sex (male and female) were calculated as W = 0.18122.601 with R2 = 0.900. From this study showed it could be stated that crabs have allometric growth pattern. The Fulton&rsquo;s condition factor (Kn) value were calculated as 1.10 and sex ratio calculated was 1:1.49. This paper provides information.&nbsp;

Carapace Length-weight, Carapace Width-weight Relationships, Condition Factor and Sex Ratio of Freshwater Crab Sartoriana spinigera (Wood-Mason, 1971) from the River Burhi Gandak, North Bihar, India