HUMAN ACTIVITIES ALTER

HYDROLOGICAL CYCLE

TANG QIUHONG

Human activities alter hydrological cycle

• Introduction• Research area

• Some ideas

Human Domination of Earth’s Ecosystems[1]

Modified from Peter M. Vitousek et al.[1]

Human alteration of earth is substantial and growing.

(Modified from [5])

Human activities & hydrological cycle[2,3,4]

• Most of human activities that alter rainfall-runoff flow is unconscious.

• The actions people manage water resources are the actions people try to influence dissipative flow.

Land transformation Intake from river, reservoir …

Focus on Dissipative Flow

• Flow or seepage to ‘lowland’ because of hydraulic head without human interpose

• To simulate NDF we need know groundwater, elevation well. But “the inability to describe heterogeneity in aquifer characteristics is a fundamental problem in groundwater hydrology and will continue.”[6]

1.Natural Dissipative flow (“without human interpose”)

Spring

(Modified from William M. Alley et al [6])

2.Manmade Dissipative flow (“direct human interpose”)

RiverSoil water

GroundwaterCity

irrigated land

70% of man-used water is used in agriculture[7]

Use population, economic growth etc to estimate it . (about 30%)

Soil water

Groundwater

NON-irrigated land

Root zone

Groundwater

P E E

Soil water Soil water

Water content is controlled

Visualization(Modified from Illinois Water Resources Center (IWRC) [8])

Runoff flow (direct):Surface runoff is lagged by ridge of field.

Dissipative flow (direct):Keeping soil moist when it is dry.

<indirect>Human activities affect latent and sensible fluxes to the atmosphere.Feedback to atmosphere (evaporation, albedo, etc)

PEFeedback

Human activities alter hydrological cycle

• Introduction

• Research area• Some ideas

Scale• We need to incorporate the mechanics of soil

moisture redistribution, and this demand us to predicate the response of this system on a timescale not long.

• Type of soil and vegetation should be specified (We need to consider groundwater because a shallow water table provides moisture for the soil and vegetation and such acts as a source term for evapotranspiration to the atmosphere[9]. Of cause, because of the inability to know spatial heterogeneity, we should simplified it ). This limits the spatial scale.

• Research area: a catchment (Yellow River)• Timescale: month (timestep: days/hours)

Why We Choose Yellow River

We should choose a river basin in semiarid area.arid area: no efficient runoff flow(e.g. Tarimu River )humid area: dissipative flow is not remarkable

Fig 1. Comparison between precipitation of 1998 and perennial in Yellow River[10]

Fig 2. Comparison between streamflow of 1998 and perennial in Yellow River [10]

perennial

perennial

Human activities alter hydrological cycle

• Introduction

• Research area

• Some ideas

Model description()

1. Coupling with atmosphere2. Physically base on Soil water model3. Consider Groundwater4. Watershed-scale

Horizontal boundary conditionsGiven by a large scale model (GCM or a nested grid model) (pressure, humidity, temperature, wind gradients …)

Internal Cycle (Timestep: hours or less?)To calculate (atmosphere radiation, wind speed, pressure, humidity, temperature, and precipitation)

(FAO) Penman-Monteith equation:

Soil & Vegetation

Groundwater

Atmosphere

Model description()

Atmosphere-Soil interaction1.Atmosphere model gives parameters for Penman-Monteith equation -> Evaporation (latent heat flux)2. Atmospheric radiation -> sensible heat flux

land use type

Root zone water balanceSoil & Vegetation

Groundwater

Atmosphere

Soil water

Groundwaterirrigated land

Soil water

GroundwaterNON-irrigated land

Irrigation (soil moisture) P P

hortonian overland flow

saturation overland flow( water table rises above the land surface)

Et

Evapotranspiration from water tableIf water table depth >5m, it is zero.

Model description()

Groundwater balance

Soil & Vegetation

Groundwater

Atmosphere

Soil water

Groundwaterirrigated land

Soil water

GroundwaterNON-irrigated land

RiverExchange

Exchange =f(water level,water table) ?depended on elevation

embankment

?

Model description(total)

grid of large scale model

Atmosphere

Land surface

Soil water

Ground waterCycle in atmosphere (interaction) Penman-Monteith equation (no data)

Groundwater (initial water table)

given by repeatedly running the model (not sure)

Riverway storage (including reservoir, lake) we should give a simple operation rule on it[12].

Next stepSpecify the research areaCollect datasetCoding ,put it into action……

行勝於言Acts speak louder than words.

(from Tsinghua Alumni Association Website, URL: http://www.tsinghua.org.cn/ )

Reference• [1] Vitousek et al., Human Domination of Earth's Ecosystems, Science 1997 277: 494-499 • [2] 干旱区平原绿洲耗散型水文模型—— I ：模型结构 , 胡和平 , 汤秋鸿 , 田富强 , 水科学进

展 （已接受） (in Chinese)HU Heping, TANG Qiuhong, and TIAN Fuqiang. A Dissipative Hydrological Model for Arid Plain Oasis, I: Model Structure, Advance in water science, (in press)

• [3] 干旱区平原绿洲耗散型水文模型—— II ：模型应用 , 汤秋鸿 , 田富强 , 胡和平 , 水科学进展 （已接受） (in Chinese)TANG Qiuhong, TIAN Fuqiang, and HU Heping. A Dissipative Hydrological Model for Arid Plain Oasis, II: Applications of Model, Advance in water science, (in press)

• [4] 基于散耗流的流域水文模型研究 , 胡和平 , 汤秋鸿 , (in Chinese, English version is under construction) HU Heping, TANG Qiuhong. A Study of Hydrological Model Based on Dissipative Flow, (personal document).

• [5] The Environment in Tokyo - Aquatic Environment 2/2. URL: http://www.kankyo.metro.tokyo.jp/kouhou/english2001/we_2.htm

• [6] Alley et al., Flow and Storage in Groundwater Systems, Science 2002 296: 1985-1990 • [7] Human Appropriation of Renewable Fresh Water ,Sandra L. Postel, Gretchen C. Daily,

and Paul R. Ehrlich , Science 9 February 1996; 271: 785-788 (in Reports).• [8] Website of Illinois Water Resources Center (IWRC) URL: http://www.environ.uiuc.edu/

iwrc/faq.htm

AcknowledgeSome of the ideas come from reference [9] and [12]. Also I would like to appreciate my supervisor Dr. HU Heping in Tsinghua University, Beijing China for references [2][3][4].

Reference (continued)• [9] York, J. P., M. Person, W.J. Gutowski and T. C. Winter, 2002: Putting aquifers into

atmospheric simulation models: An example from the Mill Creek Watershed, northeastern Kansas. Adv. Wat. Res., 25, 221-238.

• [10] 黄河水资源公报 , 水利部黄河水利委员会 (in Chinese) Bulletin of Yellow River water resources, Yellow River Conservancy Commission, ministry of water resources of the People’s Republic of China.

• [11] Gutowski, W. J., C. J. Vorosmarty, M. Person, Z. Otles, B. Fekete and J. York, 2002: A Coupled Land-Atmosphere Simulation Program (CLASP). J. Geophys. Res., 107 (D16), 4283,10.1029/2001JD000392

• [12] Chong LI, Dawen YANG, Guangheng NI and Heping HU, 2004: Simulation of irrigation consumption in the Yellow River basin using a distribution hydrological model. (in press, personal communication)