Experience with modelling of runoff formation processes at basins of different scales using data of representative and experimental watersheds Olga Semenova State Hydrological Institute St. Petersburg, Russia

1.Models need parameters values 2.The problem of heterogeneity Example: infiltration coefficient of the upper soil layer 3.Idealized representative slope 4.The problem of calibrationIntroduction Areal extent, m 2 Cv (filtration tube) (field filtration device) (sprinkling-machine) (elementary watershed, estimation in inverse way by observations of precipitation and surface runoff) 0

Objectives: to demonstrate that using observational data of small jointly with the appropriate modelling algorithms gives the possibility to avoid the calibration procedure and transfer estimated parameters (without change for a given landscape zone) to other basins, including those with scarce availability of information.

Main principles of model development Universality (response to PUB challenge) Balance between simple solutions and adequate description of natural processes Apriori estimation and systematization of main parameters (without calibration for any new object) Routine forcing data

Deterministic Modelling Hydrological System (DMHS or model “Hydrograph”, by Prof. Yu.B. Vinogradov)

DMHS features DistributedDistributed Calculating interval – 24-hour or lessCalculating interval – 24-hour or less Forcing data – precipitation, temperature and humidityForcing data – precipitation, temperature and humidity Output – runoff hydrograph, water balance elements, state variables of soil and snow coverOutput – runoff hydrograph, water balance elements, state variables of soil and snow cover DMHS key concepts Concept of runoff formation complexes Concept of runoff elements (see for details Vinogradov 2003, 2008) DMHS parameters Soil properties Vegetation cover properties Slope surface Underground water Climate parameters

The spatial-computational schematization of the basin

What do we need from small watersheds? Observational data on representative basins to calibrate some model parameters Evaluation and systematization of the representative landscape properties (i.e. apriori assessment of model parameters) Understanding of the processes and its clear and proved explanation Understanding of the models and their objective and active evaluation Mutual interaction between modellers and experimentalists What do we need from experimentalists?

Study objects * * * * * Nizhnedevitskaya Water Balance Station Valday experimental station (research is still in progress) Mogot experimental plot Kolyma Water Balance Station Suntar-Hayata range geophysical station MildCLIMATEExtreme Plain, hillyRELIEFMountainous SteppeLANDSCAPETundra, taiga SeasonalPERMAFROSTContinuous

PRELIMINARY RESULTS I. Nizhnedevitskaya water balance station SOIL TEMPERATURE 0.2 m 0.8 m

SNOW CHARACTERISTICS Snow height at Nizhnedevitskaya observational station

SOIL MOISTURE Stream Dolgy, area 2.51 km 2, content of moisture in 1-m layer

RUNOFF Sosna river at Elec, area km 2 Devica river at Tovarnya, area 103 km 2

II. Kolyma water balance station SOIL TEMPERATURE 0.4 m 0.8 m

RUNOFF Yuzhny stream, area 0.27 km 2

Detrin at Vakhanka river mouth, area 5630 km 2

Kolyma at Kolymskoye, basin area km 2

Suntar at Sakharynia river mouth, area 7680 km 2 III. Suntar-Hayata range experimental station

Yana at Dgangky, area km 2

Nelka at Mogot, area 30.8 km 2 III. Mogot experimental plot

Katyryk at Toko, basin area 40.2 km 2

Timpton at Nagorny, area 613 km 2

Uchur at Chyul’bu, area km 2

Statistics on observed vs simulated flow (averaged for all basins in Eastern Siberia) DailyYear Nash-Sutcliffe Relative error (in absolute value) 36 %10 %

Conclusions The results aim to demonstrate the possibility of a single hydrological model application for: (1)runoff simulations at large-scale basins, as well as for fine time step representation of individual hydrological process at the local scale; (2)simulation at various landscape and climate zones with different driving processes. The observations should be carried in tight interaction with the development of hydrological models, i.e. the experiments and observations schemes and components are to be coordinated in order to be used in the adoption or rejection of current hydrological theories and assumptions. Desired future

REFERENCES (in English) Vinogradov, Yu.B., 2003a, River Runoff Modeling in Hydrological Cycle, edited by I.A. Shiklomanov, in Encyclopedia of Life Support Systems (EOLSS), Developed under the auspices of the UNESCO, Eolss Publishers, Oxford, UK, [ Vinogradov, Yu.B., 2003b, Runoff Generation and Storage in Watershed in Hydrological Cycle, edited by I.A. Shiklomanov, in Encyclopedia of Life Support Systems (EOLSS), Developed under the auspices of the UNESCO, Eolss Publishers, Oxford, UK, [