@article{fdi:010068105,
  title = {{C}hanges in lakes water volume and runoff over ungauged {S}ahelian watersheds},
  author = {{G}al, {L}. and {G}rippa, {M}. and {H}iernaux, {P}. and {P}eugeot, {C}hristophe and {M}ougin, {E}. and {K}ergoat, {L}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A} large part of the {S}ahel consists of endorheic hydrological systems, where reservoirs and lakes capture surface runoff during the rainy season, making water available during the dry season. {M}onitoring and understanding the dynamics of these lakes and their relationships to the ecohydrological evolution of the region is important to assess past, present and future changes of water resources in the {S}ahel. {Y}et, most of {S}ahelian watersheds are still ungauged or poorly gauged, which hinders the assessment of the water flows feeding the lakes and the overall runoff over their watershed. {I}n this paper, a methodology is developed to estimate water inflow to lakes for ungauged watersheds. {I}t is tested for the {A}goufou lake in the {G}ourma region in {M}ali, for which in situ water height measurements and surface areas estimations by remote sensing are simultaneously available. {A} {H}eight-{V}olume-{A}rea ({HVA}) model is developed to relate water volume to water height and lake surface area. {T}his model is combined to daily evaporation and precipitation to estimate water inflow to the lake, which approximates runoff over the whole watershed. {T}he ratio between annual water inflow and precipitation increases over the last sixty years as a result of a significant increase in runoff coefficient over the {A}goufou watershed. {T}he method is then extended to derive water inflow to three other {S}ahelian lakes in {M}auritania and {N}iger. {N}o in situ measurements are available and lake surface areas estimation by remote sensing is the only source of information. {D}ry season surface area changes and estimated evaporation are used to select a suited {VA} relationship for each case. {I}t is found that the ratio between annual water inflow and precipitation has also increased in the last 60 years over these watersheds, although trends at the {M}auritanian site are not statistically significant. {T}he remote sensing approach developed in this study can be easily applied to recent sensors such as {S}entinel-2 or {L}andsat-8, to quantify the evolution of hydrological systems in ungauged {S}ahelian regions.},
  keywords = {{S}ahel ; {L}ake ; {U}ngauged watershed ; {R}emote sensing ; {W}ater inflow ; {MALI} ; {SAHEL}},
  booktitle = {},
  journal = {{J}ournal of {H}ydrology},
  volume = {540},
  numero = {},
  pages = {1176--1188},
  ISSN = {0022-1694},
  year = {2016},
  DOI = {10.1016/j.jhydrol.2016.07.035},
  URL = {https://www.documentation.ird.fr/hor/fdi:010068105},
}