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Lake El'gygytgyn Water and Sediment Balance Components Overview

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Lake El'gygytgyn Water and Sediment Balance Components Overview Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Clim. Past Discuss., 8, 3977–4001, 2012 www.clim-past-discuss.net/8/3977/2012/ Climate doi:10.5194/cpd-8-3977-2012 of the Past CPD © Author(s) 2012. CC Attribution 3.0 License. Discussions 8, 3977–4001, 2012 This discussion paper is/has been under review for the journal Climate of the Past (CP). Lake El’gygytgyn Please refer to the corresponding final paper in CP if available. water and sediment balance components overview Lake El’gygytgyn water and sediment G. Fedorov et al. balance components overview and its Title Page implications for the sedimentary record Abstract Introduction Conclusions References G. Fedorov1, M. Nolan2, J. Brigham-Grette3, D. Bolshiyanov4, G. Schwamborn5, 6 and O. Juschus Tables Figures 1Arctic and Antarctic Research Institute, Bering Street 38, 199397 St. Petersburg, Russia 2Water and Environmental Research Center, Institute of Northern Engineering, 306 Tanana J I Drive, Duckering Room 437, University of Alaska Fairbanks, Fairbanks, Alaska 99775-5860, USA J I 3 Department of Geosciences, University of Massachusetts, P.O. Box 35820, Amherst, Back Close MA 01003-5820, USA 4 St. Petersburg State University, Faculty of Geography and Geoecology, 10 line V.O., 33, Full Screen / Esc 199178 St. Petersburg, Russia 5 Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg, Printer-friendly Version 14471 Potsdam, Germany 6 Institute of Applied Geology, Technical University of Berlin, Ackerstrasse 76, Sek ACK 1-1, Interactive Discussion 13355 Berlin, Germany 3977 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Received: 31 July 2012 – Accepted: 9 August 2012 – Published: 22 August 2012 Correspondence to: G. Fedorov ([email protected]) CPD Published by Copernicus Publications on behalf of the European Geosciences Union. 8, 3977–4001, 2012 Lake El’gygytgyn water and sediment balance components overview G. Fedorov et al. Title Page Abstract Introduction Conclusions References Tables Figures J I J I Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion 3978 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Abstract CPD Modern process studies of the hydrologic balance and sediment flux into and out of Lake El’gygytgyn, central Chukotka, provide important quantitative estimates for better 8, 3977–4001, 2012 understanding the lacustrine paleoclimate record from this basin. Formed ca. 3.6 Ma 5 as a result of a meteorite impact, the basin contains one of the longest paleoclimate Lake El’gygytgyn records in the Arctic. Fluvial activity into the basin today is concentrated over the short water and sediment snowmelt period. Recent lake-level changes have a slow regressive character due to balance components active underground runoff, even during winter. The residence time of the lake-water is overview estimated to be about 100 yr. The main source of clastic material are incoming steams. 10 The amount of sediment discharge through the outflow river is insignificant and com- G. Fedorov et al. pletely compensated even by little aeolian input. Title Page 1 Introduction Abstract Introduction Lake El’gygytgyn is located in Central Chukotka, Far East Russian Arctic (67◦300 N and Conclusions References 172◦50 E; Fig. 1), approximately 100 km north of the Arctic Circle. The lake has an al- 15 most square shape and a diameter of about 12 km in filling a portion of a meteorite Tables Figures impact crater that is 18 km in diameter. The crater formed 3.6 million yr ago (Layer, 2000). Based upon previous geomorphologic and geological research (Glushkova, J I 1993) this territory was never glaciated and sedimentation in the lake presumably has been continuous since its formation. In winter season of 2008–2009, deep drilling J I 20 of Lake El’gygytgyn recovered long cores embracing both the entire lacustrine sedi- Back Close ment sequence (318 m) from the center of the basin and a companion core 141.5 m long, into permafrost from outside the talik surrounding the lake (Melles et al., 2012; Full Screen / Esc Brigham-Grette et al., 2012). These cores now provide the science community with the longest terrestrial paleoenvironmental record from the Arctic, starting in the warm Printer-friendly Version 25 middle Pliocene (Melles et al., 2012; Brigham-Grette et al., 2012). Interactive Discussion 3979 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | This paper provides the results of water and sediment balance investigations at Lake El’gygytgyn obtained during pre-site surveys (expeditions in 2000 and 2003). Knowl- CPD edge of modern hydrological and sediment supply processes is critically important as 8, 3977–4001, 2012 a baseline to inform us concerning the sensitivity of basin sedimentology to climate 5 forcing in the past. An overview of the lake’s setting, basin morphologic parameters, modern meteo- Lake El’gygytgyn rological characteristics and lake crater hydrology were first provided by Nolan and water and sediment Brigham-Grette (2007). Lake El’gygytgyn with an area of 110 km2 and volume of balance components 14.1 km3 is today 175 m deep surrounded by a watershed measuring 293 km2 (Nolan overview 10 and Brigham-Grette, 2007). The lake has approximately 50 inlet streams and an outlet, the Enmyvaam River (Fig. 1) that belongs to the Anadyr River drainage basin leading G. Fedorov et al. to the Bering Sea. The lake level elevation is 492.4 m according to recent topographic maps. Title Page Data from an automated meteorological station installed at the southern lake shore 15 near the outflow river in 2000 (Nolan and Brigham-Grette, 2007; Nolan, 2012) shows Abstract Introduction that over the period from 2001 to 2009 the average air temperature was −10.2 ◦C with extremes from −40 ◦C to +28 ◦C, and liquid precipitation averaged 73 mm (summer Conclusions References rainfall) in the region. The mean annual amount of liquid precipitation during 6 yr over Tables Figures the period from 2002–2007 was 126 mm with extremes from 70 mm in 2002 to 200 mm 20 in 2006 (Nolan, 2012). J I The onset of the spring flooding and first motes of open water typically appear along the lake shore in the beginning of June. The lake ice completely disappears in the J I middle of July and freezing starts again by the middle of October (Nolan et al., 2003). Back Close A first appraisal of the Enmyvaam River discharge velocity at its the head was done −1 25 by Glotov and Zuev (1993), which was nearly equal to 1 m s . These data allowed Full Screen / Esc them to estimate a water discharge of 50 m3 s−1 at a maximum, but with an average 3 −1 in the range of 20 m s (Glotov and Zuev, 1995). First instrumental measurements of Printer-friendly Version water discharge were performed in summer 2000 (Nolan and Brigham-Grette, 2007). For this updated study, measurements were done three times in the Enmyvaam River Interactive Discussion 3980 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | head and once in most of the inlet streams. Water discharge in the Enmyvaam River was 19.8 m3 s−1 on 16 August, 14.2 m3 s−1 on 23 August, and 11.6 m3 s−1 on 1 Septem- CPD ber and in each inlet streams less than 1 m3 s−1. Notably timing is everything, given 8, 3977–4001, 2012 that the outlet is closed until late June when the lake level rises enough to breach and 5 quickly downcut through fall season longshore drift choking the outlet. Moreover, dur- ing summers inlet streams are largely reduced to a trickle or dry up completely after Lake El’gygytgyn the late spring freshet. water and sediment balance components overview 2 Methods G. Fedorov et al. The following formula can be applied to estimate Lake El’gygytgyn water balance: 10 Y = Y1 + Y2 + P + Z1 − Z2 − E Title Page – Y = Enmyvaam River runoff; Abstract Introduction – Y1 = main lake tributaries runoff; Conclusions References – Y2= remaining stream network runoff; Tables Figures – P = precipitation over the lake surface; 15 Z – 1 = ground water influx; J I – Z = underground runoff; 2 J I – E = evaporation from the open water surface. Back Close 2.1 Enmyvaam River, main lake tributaries and remaining stream Full Screen / Esc network runoffs Printer-friendly Version 20 Methods of measurement and subsequent calculations were done in accordance with Russian hydrometeorological survey standards (Guide to Hydrometeorological sta- Interactive Discussion tions, 1978). 3981 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | During summer 2003 the water discharge in the Enmyvaam River (outflow) and main inlet streams (Fig. 1) were measured three times at the beginning, middle and end of CPD the summer season. A standard current velocity meter was used to measure flowrates. 8, 3977–4001, 2012 The water discharge was calculated according to the prescribed analytical method 5 (Guide to hydrometeorological stations, 1978). Average seasonal water discharge and subsequently seasonal runoff were then calculated for each measured stream. The Lake El’gygytgyn stream’s watershed area provided by Nolan and Brigham-Grette (2007) was used to water and sediment calculate the seasonal unit area discharge (ratio between the water runoff and water- balance components shed area) for those main streams. For the unmeasured streams we used the average overview 10 unit area discharge of the measured steams. Thus, we can calculate the seasonal unit area discharge for the entire drainage basin except of the lake itself. The total seasonal G. Fedorov et al. water runoff is calculated as the seasonal unit area discharge multiplied by total water- shed area. The Enmyvaam River total runoff is estimated as average water discharge Title Page multiplied by time period of outflow activity. Abstract Introduction 15 2.2 Precipitation over the lake surface Conclusions References Precipitation over the lake surface was estimated as the sum of liquid precipitation directly to the lake water surface during summer plus the melted snow supply from Tables Figures the seasonal lake ice.
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