Farm produce on 1.61 lakh hectares of land has been damaged so far as per a survey.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/bihar-floods-toll-mounts-61-over-31-lakh-affected
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/indian-express-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/bihar
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/floods
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/rivers
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/gopalganj-d
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/katihar-d
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/displacement
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/rainfall
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/natural-disasters