Quantification and mapping of solute travel times in catchments: Spatial, statistical and source/flowspecific distributions Gia Destouni Stockholm University State of the art of catchment-scale residence time: conceptualization, modeling and analysis • Own pathway into this problem field: >25 year history of theoretical developments on the solute travel/arrival time - mass flux connection and conceptualization for unsaturated zone, groundwater, stream networks, coupled systems and whole catchments • Examples of ongoing work on reactive solute (nutrient, pollutant) transport-biogeochemistry on catchment scale Stochastic solute advection in 1D porous media: Simmons (1982) Basin-scale solute transport: Rinaldo and Marani (1987) Reactive solute transport in heterogeneous aquifers: Cvetkovic and Shapiro (1990) Reactive solute transport through unsaturated zone to groundwater: Destouni and Cvetkovic (1991) Generalized solute travel time - mass flux framework for heterogeneous aquifers: Dagan et al. (1992) Generalized framework for solute travel time - mass flux uncertainty in heterogeneous aquifers: Cvetkovic et al. (1992) Reactive solute travel time - mass flux uncertainty in unsaturated zone: Destouni (1992) Generalized 3D conceptualization of reactive solute travel time - mass flux in heterogeneous aquifers: Cvetkovic and Dagan (1994) Reactive solute travel time - mass flux in coupled soil non-uniform groundwater system: Destouni and Graham (1995) Non-linear reaction extension for solute travel time - mass flux concept in heterogeneous aquifers: Simmons et al. (1995) Immiscible flow - reaction system extension for solute travel time - mass flux concept in heterogeneous aquifers: Dagan and Cvetkovic (1996) Cachment-scale 18O transport interpretation with stochastic travel time - mass flux concept: Simic and Destouni (1999) Extensions to multi-component reactive solute transport Metal transport-precipitation-dissolution: Eriksson and Destouni (1997) General multi-component transport-reaction model: Yabusaki et al. (1998) Hydrocarbon transport-biodegradation: Kaluarachi et al. (2000) Radionuclide transport-reaction system: Tompson et al. (2002) Coupling with general geochemical PHREEQC model: Malmström et al. (2004) Extensions to transport-mass transfer-reactions on catchment scales … What we hear more about in this workshop The Abiskojokken catchment, 566 km2 - travel time quantification for permafrost change - C and weathering product cycling investigations see poster by Lyon et al. The Forsmark catchment area, 30 km2- fine-resolution travel time quantification for generic solute transport investigations The Norrström drainage basin, 22!103 km2 - travel time quantification for nutrient transport and generic largebasin solute transport investigations Hannerz & Destouni, 2006 Nutrient mass flows in the Norrström drainage basin 22!103 km2 Studied extensively with different modelling approaches: Baresel and Destouni, 2005, 2006; Darracq et al., 2005, 2008; Darracq and Destouni, 2005,2007; Destouni and Darracq, 2006; Destouni, 2007; Lindgren et al., 2007; Darracq et al., 2008 7 Total mass load from all sources to the recipient Quaternary deposits i i ! gw"s # gw"s Fractured rock (1! " i gw!s )# i gw Mass inputs from different sources General advective solute travel time definition along any source-to-recipient pathway: Moving coordinate system along transport pathway xCP p direction !p = " dx a v(x p ) Xp=XCP Xp V(Xp) Control plane Example linkages between physical travel time and biogeochemical attenuation rate that yield delivered mass fraction to Control Plane/Recipient from any source i: Through soil-gw to stream or directly to other recipient (lake, coast) 1 i !gw (xCP ) = i Agw & % % exp[" # $ (agw ,xCP )]ggw($ gw;agw ,xCP )d$ gwdagw gw gw i 0 Agw From direct input or from soil-gw system to stream to recipient (lake, coast) 1 !si = i As & % % exp[" #$ (a ,x s s s out )] fs($ s;as ,xout )d$ sdas 0 Asi Extended from Lindgren and Destouni (2004) Without slow/deep (?) gw transport ! (years) 0 0.1 0.2 0.5 1 2 3 4 5 10 0 20 km ± With slow/deep gw (?) transport 20 200 1000 Travel time CDF in water subsystem j and in combined Norrström Cumulative distribution 1 0.8 0.6 in surface water, to outlet in surface runoff, to outlet 0.4 in groundwater, to nearest downstream surface water 0.2 in combined Norrström, to outlet 0 0.01 0.1 1 10 100 Travel time (year) 1000 Total mass delivery fraction !=9.10-6/year 1 0 !=9.10-6 /year ± 0 50 km !=9.10-5 /year !=9.10-5 /year !=9.10-4 /year !=9.10-4/year Studied extensively in connection with nuclear waste repository studies: numerous technical SKB reports and, e.g., Jarsjö et al. (JHydrol, 2008), Destouni et al. (GRL, 2008), Destouni et al. (in review 2009) Physical (advective) solute travel times to the coast (yr) Transport through groundwater Transport through groundwater and stream network Hypothetical source location-extent examples Delivered mass fraction to the coast Transport through groundwater Transport through groundwater and stream network Workshop definition: Residence time - the transit time from the soil surface to the stream channel Needs for catchment-scale nutrient-pollutant transport applications: • More general travel time definition, with dependencies on various source-to-recipient pathways • Source-specific travel time distributions • Spatio-(temporal) and randomness dependencies of travel times and travel time distributions for different flow-transport conditions • Travel time role in general, spatially distributed, mechanistic conceptualization of multi-source transportbiogeochemistry over whole catchment scales