the early bird may get the worm… but the second mouse gets the cheese. u6115: water monday, july...

The early bird may get the worm…

but the second mouse gets the cheese.

U6115: WaterMonday, July 19 2004

One thing we should remember from this summer(and the last 6…)

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• Intro to Hydrology

• Systems and Cycles• Flux, Source/Sink, Residence time, Feedback mechanisms…

Today: Water/Hydrology

U6115 Syllabus: Course Outline

• The water cycle part of the class is focused on basic physical principles (evaporation, condensation, precipitation, runoff, stream flow, percolation, and groundwater flow), as well as environmentally relevant applications based on case studies.

• Most specifically, students will be exposed to water quantity and issues from global to regional scales and how human and natural processes affect water availability in surface and groundwater systems.

• Note: water quality issues will be mentioned but only briefly since they have been covered more extensively in the Environmental Chemistry course (ENVU6220)

U6115 Syllabus: Course Outline

1)1) Class 1Class 1: (July 19) Introduction - Water for the world - : (July 19) Introduction - Water for the world - Lab 1:Lab 1: Global and regional water budgets Global and regional water budgets

2)2) Class 2Class 2: (July 26) Global water issues - Hydrological cycle - : (July 26) Global water issues - Hydrological cycle - Lab 2Lab 2: Hydrological Forecasts and : Hydrological Forecasts and their Communication to Decision-Makerstheir Communication to Decision-Makers

3)3) Class 3Class 3: (August 02) Dams & Reservoirs - : (August 02) Dams & Reservoirs - Lab 3Lab 3: Reservoirs and greenhouse gases : Reservoirs and greenhouse gases

4)4) Class 4Class 4: (August 09) Condensation/Precipitation – Streamflow/Floods - : (August 09) Condensation/Precipitation – Streamflow/Floods - Lab 4Lab 4: Precipitation and : Precipitation and Flood predictions: A Statistical AnalysisFlood predictions: A Statistical Analysis

5)5) Class 5Class 5: (August 16) Evaporation - Droughts – Land Use Impact on Streamflow: (August 16) Evaporation - Droughts – Land Use Impact on Streamflow

6)6) Class 6Class 6: (August 18) Groundwater flow - Groundwater transport: (August 18) Groundwater flow - Groundwater transport

Wk 8 - Jul 18-24 18-Jul 19-Jul 20-Jul 21-Jul 22-Jul9:30AM-12:00PM Water 1 Environ. Policy Toxico 2 Pop 8

1-2PM Final Exam Pre-lab Meeting Workshop Pre-lab Meeting Pre-lab Meeting2-4PM (1-3PM) Climate Water 1 Lab-a Toxico 2 Lab-a Pop 8 Lab-a4-6PM Water 1 Lab-b Toxico 2 Lab-b Pop 8 Lab-b

Wk 9 - Jul25-31 25-Jul 26-Jul 27-Jul 28-Jul 29-Jul9:30AM-12:00PM Water 2 Environ. Policy Toxico 3 Pop 9

1-2PM Pre-lab Meeting Workshop Pre-lab Meeting Pre-lab Meeting2-4PM Water 2 Lab-a Toxico 3 Lab-a Pop 9 Lab-a4-6PM Water 2 Lab-b Toxico 3 Lab-b Pop 9 Lab-b

Wk 10 - Aug 1-7 1-Aug 2-Aug 3-Aug 4-Aug 5-Aug9:30AM-12:00PM Water 3 Environ. Policy Toxico 4 Pop 10


Wk 11 - Aug 8-14 8-Aug 9-Aug 10-Aug 11-Aug 12-Aug9:30AM-12:00PM Water 4 Environ. Policy Toxico 5 Pop 11


Wk12 - Aug 15-19 15-Aug 16-Aug 17-Aug 18-Aug 19-Aug9:30AM-12:00PM Water 5 Environ. Policy Water 6 Exam Pop/Land

1-2PM Pre-lab Meeting Workshop2-4PM Water 5 Lab-a4-6PM Water 5 Lab-b

NJ

Water (40% of grade) Labs: 100% (4 formal labs)

Mostly minds-on experiments with computers. Lab report due

U6115 Syllabus: Grading (activities)

Water for the WorldWater for the WorldThe role of water is central to most natural processes

• transport– Weathering, contaminant transport

• energy balance

– transport of heat, high heat capacity

• greenhouse gas

– ~ 80% of the atmospheric greenhouse effect is caused by water vapor

• life

– for most terrestrial life forms, water determines where they may live; man is exception

HydrologyHydrology

• literally "water science," encompasses the study of the occurrence and movement of water on and beneath the surface of the Earth

• finite though renewable resource– finite in quantity, unlimited in supply, use rate is

limited by 'recycling times'• hydrologic sciences have pure and applied aspects

– how the Earth works– scientific basis for proper management of water

resources (or any natural resource…)

Introduction to hydrologyuse of water in 20th century has grown dramatically

After Berner and Berner, 1987

Oceans

97%

Water on land3%

74%

11%

14%

1%

Ice caps and glaciers

Shallow groundwater (<750 m)

Deep groundwater (750-4000 m)

Lakes, soil moisture, atmosphere, rivers

Inventory of water on Earth

Cycle ApproachSome Definitions

Transport and transformation processes within definite reservoirs: Carbon, Rock, Water Cycles

Reservoir: (box, compartment: M in mass units or moles) An amount of material defined by certain physical, chemical, or biological characteristics that can be considered homogeneous

– O2 in the atmosphere– Carbon in living organic matter in the Ocean– Water in the Ocean

Flux: (F) The amount of material transferred from one reservoir to another per unit time (M/s or M/s.L2)

– The rate of evaporation of water from the surface Ocean– The rate of deposition of inorganic carbon (carbonates on marine

sedimentsSource: (I or Q) A flux of material into a reservoirSink: (O or S) A flux of material out of a reservoir

More Definitions…Budget: A balance sheet of all sources and sinks of a reservoir.

If sources and sinks balance each other and do not change with time, the reservoir is in steady-state (M does not change with time). If steady-state prevails, then a flux that is unknown can be estimated by its difference from the other fluxes.

for a control volume this means: dM/dt = I'-O'Turnover time: The ratio of the content (M) of the reservoir to

the sum of its sinks (O) or sources (I). The time it will take to empty the reservoir if there aren’t any sources. It is also a measure of the average time an atom/molecule spends in the reservoir. Or:

0 = M/O (or M/I) Cycle: A system consisting of two or more connected

reservoir, where a large part of the material (energy) is transferred through the system in a cyclic fashion

The Water (Hydrologic) The Water (Hydrologic) CycleCycle

The Water Cycle (in detail)The volume (M) of water at the surface of the Earth is

enormous: 1.37 109 km3! (total reservoir) – The Oceans cover 71% of the Earth’s surface (29% for the continent masses above sea level)

Reservoir Volume (km3) % TotalBiosphere 0.6 103 0.00004

Rivers 1.7 103 0.0001Atmosphere 13 103 0.001Lakes 125 103 0.01Groundwater 9500 103 0.68Glacial and other land ice (?) 29000 103 2.05

Oceanic water and sea ice 1,370,000 103 97.25

Total 1,408,640 103 100

Adapted from Berner & Berner (Adapted from Berner & Berner (The Global Water CycleThe Global Water Cycle; Prentice Hall, 1987); Prentice Hall, 1987)

Of total yearly evaporation, 84% evaporates from the Oceans and 16% from surface of continents.

However, return to Earth via precipitation: 75% falls directly on the Oceans and 25% on the continents.

During the year, the atmosphere transports 9% of Oceans’ evaporation to the continents!

This water is returned via surface streams and as groundwater

Fluxes (F in 103 km3/yr)

Precipitation and evaporation are difficult to measure precisely over the oceans. They are mostly estimated from models and satellite data.

Groundwater reservoir estimates bear a inherent error in the fact that they are indirectly determined.

Soil moisture and evapotranspiration rates depend on indirect measurements and average soil quality and global/regional respiration rates

Errors!

High probability that a certain fraction of the atoms or molecules forming the reservoir (M) will be of a certain age (mean age of the element when it leaves the reservoir)

The simplified residence time turnover timeThe time it would take to empty a reservoir if the sink (O or “outflow”)

remained constant while the sources were zero

0 = M/O (or M/I)

M = 0O

Residence time of water in the atmosphere

M = ?; O = ?; 0 = ?

M = 13 103 km3

S = 297(O) + 99(C) 103 km3/yr = 396 103 km3/yr

0 = 0.033 yr = 12 days!

Replacement ~30 times/year

Residence Time(years – months – weeks)

High probability that a certain fraction of the atoms or molecules forming the reservoir (M) will be of a certain age (mean age of the element when it leaves the reservoir)

The simplified residence time turnover timeThe time it would take to empty a reservoir if the sink (O) remained constant

while the sources were zero

0 = M/O (or M/I)

M = 0O

Residence time of water in the ocean

M = ?; S = ?; 0 = ?

M = 1,370,000 103 km3

S = 334 103 km3/yr (evaporation)

0 = M/S = 4102 yrs!

Residence Time(years – months – weeks)

• quantitative description applying the principle of conservation of mass

• for continents as control volume this can be written as

dV/dt = p - rso - et = 0 (all averaged)

• on average this means: p = rso+ et

• the water budget for all land areas of the world is: p=800mm, rs = 310mm, and et = 490mm

• the global runoff ration (rs/p) is ~39% there are lots of local and regional variations.

Continental Mass Balance

System Approach…Feedback: All closed and open systems respond to inputs

and have outputs. A feedback is a specific output that serves as an input to the system.

Negative Feedback (stabilizing): The system’s response is in the opposite direction as that of the output. CLOUDS!

System Approach…Positive Feedback (destabilizing): The system’s

response is in the same direction as that of the output.

59 min

Bottle half full

System Approach…Positive Feedback (destabilizing):

CLOUDS!

Surface waters

BRF

Watershed, catchment, drainage basinCatchementCatchement (drainage basin, watershed): the basic unit of (drainage basin, watershed): the basic unit of volume (control) which is an area of land in which water volume (control) which is an area of land in which water flowing across the land surface drains into a particular flowing across the land surface drains into a particular stream and ultimately flows a single point or outlet.stream and ultimately flows a single point or outlet.

dV/dt = p - rso - et = 0

on average p = rso + et

CatchmentCatchmentOur concern with Our concern with precipitationprecipitation and and evapotranspirationevapotranspiration is in is in knowing the knowing the ratesrates, timing, and spatial distribution of these , timing, and spatial distribution of these water fluxes between the land and the atmosphere.water fluxes between the land and the atmosphere.

dV/dt = p - rso - et = 0

New York

Texas

Measurement techniques

precipitation evapotranspiration

Average statewide evapotranspiration for the conterminous United States range from about 40% of the average annual precipitation in the Northwest and Northeast to about 100% in the Southwest.

Evapotranspiration

Annual Precipitation - Australia

Annual Evaporation - Australia

Annual Evapotranspiration - Australia

Rivers and Streams


discharge

flow depth (stage)

Colorado Riverhydrograph

Questions:

• When does discharge peak and why?

• The hydrographs were taken at different locations of the river, what is the difference in the hydrographs and why is there one?

• Hydrographs are variable between years

• Discharge often peaks in late winter or spring, snowmelt

• Reservoirs smooth out extremes

Colorado Riverhydrograph

Canada del Oro hydrograph

http://water.usgs.gov

extended periods with no discharge at all!

Santa Cruz River (Tucson, AZ, 1930 vs. 1964 - 1983 flood)

Lakes and Reservoirs

Reservoir distribution in the U.S.

WetlandsDefinition (U.S. Fish and Wildlife Service):

"WETLANDS are transitional systems between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water. For purposes of this classification wetlands must have one or more of the following three attributes:

(1) at least periodically, the land supports predominantly hydrophytes;(2) the substrate is predominantly undrained hydric soil; and(3) the substrate is saturated with water or covered by shallow water at some time

during the growing season of the year."

Hydrologic conditions: Groundwater (water table or zone of saturation) is at the surface or within the soil root zone during all or part of the growing season.

Hydric soils: soils that are saturated, flooded, or ponded long enough during the growing season to develop oxygen-free conditions in the upper six inches

Hydrophytic vegetation: plants typically adapted to wetland and aquatic habitats; plants which grow in water or on a substrate that is at least periodically deficient in oxygen due to excessive water content.

Wetlands are classified into two general categories: coastal and inland. Coastal wetlands are further classified into marine and estuarine categoriesInland wetlands are further subdivided in riverine, lacustrine, and palustrine wetlands.

BogPeat accumulation usually dominated by moss. Receivesonly direct precipitation; characterized by acid water, lowalkalinity, and low nutrients.

Fen

Peat accumulation; may be dominated by sedge, reed,shrub or forest. Receives some surface runoff and/orground water, which has neutral pH and moderate to highnutrients.

MireUsed mainly in Europe to include any peat-forming wetland(bog or fen).

MarshPermanently or periodically inundated site characterized bynutrient-rich water. In Europe, must have a mineralsubstrate and lack peat accumulation.

PlayaShallow, ephemeral ponds or lagoons that experiencesignificant seasonal changes in semi-arid to arid climates.Often have high salinity or may be completely dry.

SloughWidely used term for wetland environment in a channel orseries of shallow lakes. Water is stagnant or may flowslowly on a seasonal basis. Synonym--bayou.

SwampCharacterized by forest, shrub, or reed cover (fen).Particularly a forested wetland in North America. Dependson nutrient-rich ground water derived from mineral soils.

Wetmeadow

Open prairie, grassland or savannah with waterlogged soilsbut without standing water for most of the year.

Openwater

Deeper, normally perennial pools within wetlands andshallow portions of lakes and rivers. Ty pically home tosubmerged macrophytes.

Fens receive water from the surrounding watershed in inflowing streams and groundwater, while bogs receive water primarily from precipitation. Fens, therefore, reflect the chemistry of the geological formations through which these waters flow.









Loss of floodplain forested wetlands and confinement by levees have reduced the floodwater storage capacity of the Mississippi by 80 percent increasing dramatically the potential for flood damage.

The 1993 flood proved this prediction to be true and resulted in immeasurable damage



Benefits of Wetlands

Coastal WetlandsTidal coastal wetlands store carbon densely, holding on to 10% of the global stock of soil organic carbon in only 0.1% of the Earth’s surface. Despite their relatively small area (203 103 km2), tidal coastal wetlands may act as substantial sinks for atmospheric carbon due both to exceptional carbon burial fluxes and negligible CH4 and N2O emissions.

Because the projected sequestration efforts in North American croplands (0.5-2.5 Pg C) are of the same order of magnitude as C stocks estimated to exist in the surface meter of wetlands (~4 Pg), major losses of these ecosystems could easily offset any improvement in preservation of SOC within managed croplands even at its highest efficiency.

In many coastal regions (i.e. Louisiana Gulf Coast), these wetlands are being lost are substantial rates (50-100 km2/yr)

Groundwater

Hornberger et al., 1998

Groundwater flow is controlled by– differences in water table

(hydraulic head)

– hydraulic conductivity (relation between specific discharge – Vol/t – and hydraulic gradient)

– Hydraulic conductivity depends on both the nature of the fluid (viscosity) and the porosity of the material


Hydraulic head, conductivity

the early bird may get the worm… but the second mouse gets the cheese. u6115: water monday, july...

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