[1] Land use changes can have a significant impact on the terrestrial component of the water cycle. This study provides a comparison of three small headwater catchments in the Andean mountains of Colombia with different composition of land use. Several methods were used to quantify differences in the hydrological behavior of these catchments such as flow duration curves, stormflow analysis, and the linear reservoir concept. They were combined with an analysis of the characteristics of soils that contribute to understanding the aggregate catchment hydrological behavior. Andisols, which are soils formed in volcanic areas and with a large capacity to hold water, amplify differences in land use and limit the potential impact of land use management activities (conservation or restoration) on the water regulation function of catchments. Of the three studied catchments, less variability of flows was observed from the catchment with a larger percentage of area in forest, and a slower decrease of flows in the dry season was observed for the catchment with a relatively higher percentage of area in wetlands. Evidence is provided for the infiltration trade-off hypothesis for tropical environments, which states that after forest removal, soil infiltration rates are smaller and the water losses through quick flow are larger than the gains by reduced evapotranspiration; this is compatible with the results of the application of the linear reservoir concept showing a faster release of water for the least forested catchment.

This"article"critically"investigates"recent"water"governance"shifts,"particularly"con7 stitutional" changes" implemented" in" several" Latin" American" countries" that" high7 light"a"'right"to"water'"as"well"as"recent"efforts"that"invoke"such"a"right"in"conjunc7 tion" with" bans" on" private" water" provision" (e.g." Uruguay," Ecuador," and" Bolivia)." Drawing" on" legal" research," document" review," and" interviews," the" article" investi7 gates" the" historical," political" and" discursive" scaffolding" of" these" constitutional" changes"in"several"case"study"contexts,"including"attention"to"implementation"is7 sues"and"ongoing"challenges"following"the"reforms.""Placing"these"shifts"within"the" broader"context"of"neoliberalization"of"water"governance"of"the"past"several"dec7 ades," the" analysis" attends" to" both" the" specific" historical7contextual" formations" that"are"important"to"understand"the"constitutional"reforms,"as"well"as"the"ways" these"changes"might"be"usefully"understood"as"connected"to"broader"political"and" discursive" shifts" and" movements." Highlighting" similarities" and" differences" across" the"cases"allows"us"to"make"conceptual"contributions"to"debates"on"variegation"of" neoliberalized" natures," as" well" as" to" discussions" of" alternatives" to" neoliberalism" and"postneoliberalism."We"argue"that"although"many"of"these"reforms"are"partial," and"not"wholly"resistant"to"neoliberalism,"they"are"nonetheless"significant"for"pol7 itics"and"debates"related"to"'alternatives.'"Apart"from"resisting"particular"aspects" of"earlier"neoliberal"reforms,"they"are"also"important"to"stake"new"discursive"and" policy"terrain"on"alternative"priorities"and"uses"of"water."Further,"the"reforms"also" offer" points" of" resistance" to" the" influence" of" international" financial" institutions," transnational"corporations."

Abstract. We present a new modeling approach analyzing and predicting the Transit Time Distribution (TTD) and the Response Time Distribution (RTD) from hourly to annual time scales as two distinct hydrological processes. The model integrates Isotope Hydrograph Separation (IHS) and the Instantaneous Unit Hydrograph (IUH) approach as a tool to provide a more realistic description of transit and response time of water in catchments. Individual event simulations and parameterizations were combined with long-term baseflow simulation and parameterizations to provide a comprehensive picture of the catchment response for a long time span for the hydraulic and isotopic processes. The proposed method was tested in three Andean headwater catchments to compare the effects of land use on hydrological response and solute transport. Results show that the characteristics of events and antecedent conditions have a significant influence on TTD and RTD, but in general the RTD of the grassland dominated catchment is concentrated in the shorter time spans and has a higher cumulative TTD, while the forest dominated catchment has a relatively longer response distribution and lower cumulative TTD. The catchment where wetlands concentrate shows a flashier response, but wetlands also appear to contribute to prolong transit time.

Abstract. We present a new modeling approach analyzing and predicting the Transit Time Distribution (TTD) and the Response Time Distribution (RTD) from hourly to annual time scales as two distinct hydrological processes. The model integrates Isotope Hydrograph Separation (IHS) and the Instantaneous Unit Hydrograph (IUH) approach as a tool to provide a more realistic description of transit and response time of water in catchments. Individual event simulations and parameterizations were combined with long-term baseflow simulation and parameterizations; this provides a comprehensive picture of the catchment response for a long time span for the hydraulic and isotopic processes. The proposed method was tested in three Andean headwater catchments to compare the effects of land use on hydrological response and solute transport. Results show that the characteristics of events and antecedent conditions have a significant influence on TTD and RTD, but in general the RTD of the grassland dominated catchment is concentrated in the shorter time spans and has a higher cumulative TTD, while the forest dominated catchment has a relatively higher response distribution and lower cumulative TTD. The catchment where wetlands concentrate shows a flashier response, but wetlands also appear to prolong transit time.

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