Title: Seasonal and Interannual Patterns and Controls of Hydrological Fluxes in an Amazon Floodplain Lake With a Surface-Subsurface Process Model

Abstract

Floodplain lakes represent important aquatic ecosystems, and field-based estimates of their water budgets are difficult to obtain, especially over multiple years. We examine the hydrological fluxes for an Amazon floodplain lake connected to the Solimões River using a process-based hydrologic model. Water exchanges between the river and lake agree well with field estimates, including the timing of different hydrological phases. However, beyond available field data, modeling results show that the seven simulated years all differed from each other. These interannual differences were caused by the interplay between phases when water levels were rising with river-water flowing into the lake (RWRI), versus rising with lake-water flowing out to the river (RWLO). This exchange determines the river-water content in the lake (C_L). Maximum C_L occurred before river levels peaked because local catchment contributions can be sufficient to push lake-water out to the river, even as river levels rise. Numerical experiments show that the seasonal distribution of local rainfall, local catchment size, and interannual variability in both climate and river stage can contribute to differing dynamics of C_L in a floodplain lake. Their impacts vary among phases: river-rise dominates the RWRI, whereas local hydrological processes dominate the RWLO and receding-water phases. Intermediate-to-long-term rainfallmore » accumulation controls C_L during the RWLO phase, whereas annual precipitation accumulation is important for C_L during low water. Finally, our model generalizes beyond limited available field studies and offers potential to better understand floodplain lakes in other areas and how regional versus local changes in climate may affect their hydrological dynamics.« less

Authors:

Ji, Xinye ^[1]; Lesack, Lance F. W. ^[2]; Melack, John M.  ^[3];

• Search DOE PAGES for author "Melack, John M."
• Search DOE PAGES for ORCID "0000-0003-0619-841X"

Wang, Shilong ^[1]; Riley, William J.  ^[4];

• Search DOE PAGES for author "Riley, William J."
• Search DOE PAGES for ORCID "0000-0002-4615-2304"

Shen, Chaopeng  ^[1]

• Search DOE PAGES for author "Shen, Chaopeng"
• Search DOE PAGES for ORCID "0000-0002-0685-1901"

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+ Show Author Affiliations

1. Pennsylvania State Univ., University Park, PA (United States). Civil and Environmental Engineering
2. Simon Fraser Univ., Burnaby, BC (Canada). Geography and Biological Sciences
3. Univ. of California, Santa Barbara, CA (United States). Earth Research Inst.
4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division

Publication Date:

Tue Mar 19 00:00:00 EDT 2019

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

National Aeronautics and Space Administration (NASA); USDOE

OSTI Identifier:

1572810

Alternate Identifier(s):

OSTI ID: 1507197

Grant/Contract Number:  

AC02-05CH11231; SC0010620; SC0016605

Resource Type:

Accepted Manuscript

Journal Name:

Water Resources Research

Additional Journal Information:

Journal Volume: 55; Journal Issue: 4; Journal ID: ISSN 0043-1397

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; process-based model; Amazon; floodplain lake; river-lake exchange; connectivity; lake catchments