Water Midterm Concepts

Watershed/basin

• Area bounded peripherally by a divide and draining ultimately to a particular watercourse/body of water

• “Natural” unit for water management

• Ex. Any drop of rain that falls within Columbia River Basin will make its way by gravity into Columbia River and flow to the river’s Pacific Ocean outlet on the WA/OR border

Orthographic precipitation

• Precipitation which is caused by hills or mountain ranges deflecting the moisture-laden air masses upward, causing them to cool and precipitate their moisture

• Causes one side of mountain to have vegetation, while the other side is dry (rain shadow)

Exotic river

• river takes water from wet, humid area into dry area

Precipitation

• any liquid or solid water that forms in the atmosphere from condensed water vapor and falls to the Earth's surface under gravity

Infiltration

• Process by which water at the ground’s surface enters and permeates through the soil

  • If water infiltrates into contaminated groundwater, it is a nonrecoverable loss

Runoff

• the movement of excess precipitation or snowmelt over the land surface when the ground cannot absorb it anymore

Baseflow (return flow)

• contribution to a stream that is coming underground, groundwater entering a stream

Streamflow

• combines surface water and baseflow

Capillary force

• the ability of a liquid to rise in a narrow space against gravity due to combined cohesive forces between the liquid molecules and adhesive forces between the liquid and a solid surface

• narrower tube = stronger force = liquid level higher within tube

• causes water in soil to come up, once on surface the water evaporates with the sun (evapotranspiration)

Evaporation

• water turns from liquid to vapor by heat

• reduced evaporation/non-beneficial transpiration (invasive trees) = true water savings

Transpiration

• Water turns from liquid to vapor by plant/animal

• Increased transpiration is generally good in farming, since transpiration and yield are related

• DO NOT want to decrease transpiration for water savings (focus on reducing evaporation)

Evapotranspiration

• the combined process of water moving from the Earth's surface into the atmosphere through evaporation (from soil, water bodies, and wet surfaces) and transpiration (from plant leaves)

Aquifer

• ground completely saturated with water, above confining layer (typically rock)

• can have different confining layers at different depths, sometimes have cracks which water trickles through

Groundwater

• after it rains, water sinks into the ground and moves slowly

• fresh water that collects in the tiny pore spaces, cracks, and fractures of underground soil, sand, gravel, and rock layers

Cone of Depression

• once well begins operating, water from surrounding aquifer percolates through formation to replace water being withdrawn

• an inverted cone-shaped drop in the water table or pressure head that develops around a well when water is pumped out

• when you start pumping water out, the water is pumped from a circle, as you pump the water flows in a cone shape

Subsidence

• The sinking or settling of the land surface, which can occur when groundwater extraction reduces pressure supporting the underground sediment structure

• Compaction can be irreversible, permanently reducing the aquifer's storage capacity

• Ex. Jakarta + Mexico City

Blue, Green, Grey water

• Blue: water in a body (river, groundwater system)

  • Hydrologists traditionally work on blue water

  • Used for irrigation/drinking water

• Green: water that precipitates and infiltrates (not in a body of water)

  • Water production 

• Grey: used water that is dirty and put back into system

  • Non-consumptive use (ex. Swimming, shipping)

Hard Path versus Soft Path

• Hard path → looking for tech to increase efficiency/create new water (build dam, plant, etc)

  • Usually use hard path, but now try to use more soft path

• Soft path → changing management (laws/water pricing so ppl change behavior)

Withdrawal versus Consumption

• Withdrawal: Water removed from a source for human use

• Consumption: Water withdrawn that is not returned to the relevant water system

• Reducing withdrawals does not necessarily reduce consumption

  • Ex. a farmer installs efficient irrigation and now withdraws only 70 L instead of 100 L

    • Sounds like a 30 L water saving

    • But if previously the 60 L of unused water returned to the groundwater system and became available to other farmers, reducing withdrawal may only reduce return flow

    • At the larger basin scale, there may be little or no additional water available

Water productivity/efficiency and relationship with scale

• Produce more output with the same water and/or produce the same output with less water to free supplies for other uses

• Water efficiency at a small scale does NOT necessarily translate into water savings at a larger scale. In fact, increasing efficiency can sometimes increase total water consumption.

  • Ex. Pakistan/Indus Basin Irrigation System

  • Scale: individual farm → irrigation district→ entire river basin

• Reducing withdrawals may simply reduce return flows rather than total consumption

  • Water that appears "wasted" by one farmer may return to rivers or groundwater and be reused downstream

• Increased efficiency can incentivize farmers to expand production, increasing total water consumption (Jevon’s Paradox)

• Real water savings require reducing non-beneficial evapotranspiration or other non-recoverable losses, and controlling overall consumption

Real versus apparent water savings

• Real water savings → change in evapotranspiration

• Apparent water savings → seems like I gained water but someone else lost it

Basin closure

• Available water resources are already fully allocated or consumed, leaving little or no additional water available for new uses without reducing existing consumption or changing allocations

• It does not mean there is literally no water left in the basin

  • New infrastructure cannot automatically create additional water

  • Increasing irrigation efficiency may not generate real savings

  • New users may only gain water by taking it away from existing users or reducing non-beneficial losses

  • Management and allocation become more important than building additional supply infrastructure

• Ex. Aral Sea: when upstream agricultural withdrawals divert water away from the sea, technologies alone may not restore the Aral Sea if farmers expand production using the water they appear to save

Jevon’s paradox

• You make use of a resource more efficient/productive, thought is that you will use less of it but in reality you may use more

  • Came from the UK running out of coal, people push for more efficient coal use, Jevon said that there will actually be more coal use rather than less

  • In the context of water, more efficient water use may not actually save water, instead more water may be used

    • Productivity may increase, but water use overall is higher

Tinbergen Principle

• # goals = same # of policy levers

  • If you want to make water use more productive AND put excess water in Aral Sea, need two policy levers

• If ignored, the outcome may be the opposite

• ***people respond to incentives/changes in relative resource endowments

Prior appropriation

• Based on prior rights for gold mining: whoever was there first has first right to use whatever amount of water they need for their use (“first in time is first in right”)

  • Older right = more senior, older right takes precedence in times of shortage

    • In times of shortage, person with first right can still use first allocation (though people with later rights might have no water)

  • Users must: divert water + put water to continuous beneficial use

  • Only entitled to amount put towards beneficial use (cannot hoard more than you need for your uses)

    • No reasonable amount/use (amount you can prove you can use)

  • Priority date: date water first put to beneficial use, determines seniority of right compared to all other uses

  • Forfeiture: for nonuse (use it or lose it)

• Simple in theory, complex in practice (how to figure out who on landscape gets water 1st, 2nd, 3rd)

Riparian rights

• Right to use water = attribute attached to property rights for land (ex. own property with water running under it, automatically have right use some of water)

• Reasonable use = cannot take all of water, can only use what is defined as reasonable (multifactor analysis)

  • If there is a shortage, the shortage is shared

    • Works because a lot of precipitation = not a lot of water needed for irrigation, can reduce water proportionally and everyone has enough to get by (used for industrial/domestic/transportation)

Winter’s Doctrine

• When fed gov reserves land, it impliedly reserves a sufficient amount of water to fulfill the purposes for which reservation was created

  • Quantity = fulfill primary purposes

  • Priority date = date reservation established (NOT date put to a beneficial use)

  • Beneficial use = NO requirement that water be put to a beneficial use

  • Forfeiture = NOT subject to loss for nonuse

• Agua Caliente (2017) → Winters Doctrine also applies to groundwater

Malthus versus Boserup

• Malthus - population exponential growth, food supply linear growth

  • Resources limit people

• Boserup - population exponential growth, food supply exponential growth 

  • BECAUSE people will innovate (figure out grow more food on less land/water)

  • People create resources (human capital)

Induced innovation theory

• People innovate from the bottom up, cause of innovation = change in relative resource endowment (change in condition induces innovation)

  • Ex. lots of land and few people, slash and burn agriculture may make sense

    • As population goes up = more people per unit of land, the same techniques does not work so you need to come up with new technique

• There is NOT one water policy/law that works everywhere

  • What works in one place may make no sense elsewhere because the relationship between agriculture/people/water is different

• In context of food, one way of looking at innovation is top down = government comes up with innovation, then companies takes pieces and commercialize

Induced institutional innovation theory

• Institutions induced to work in particular set of conditions

  • Ex. laws adopted in eastern US are not the same as the western US

    • East: withdrawal rainfall patterns similar in east coast → law adopted from Romans 

    • West: consumption 

  • If conditions are different, then institutions may be different

Tragedy of the Commons

• Individuals pursuing their own short-term interests overuse a shared, limited resource, even though everyone would benefit from preserving it

• In India, every farmer has their own well pump, and would want to pump in order to maximize their agriculture output, but excessive extraction harms everyone

Access versus availability

• Availability = physical quantity of water present in a location

• Access = whether people can actually obtain and use water, which depends on infrastructure, income, energy, technology, and political power

  • In DRC, high availability but not everyone has access to clean safe water compared to Qatar

Virtual water

• Water embedded in production of food and non-food commodities

  • Ex. in SWANA, lack of water = limit ability increase agricultural production

    • SWANA imports greatest amount of grains per capita

  • Qatar’s water security = diplomacy (need to ensure shipments can come through Strait of Hormuz)

Physical versus Economic (or political) water scarcity

• Physical water scarcity: Insufficient available water relative to demand.

• Economic water scarcity: Water may exist physically, but people cannot access it because of inadequate infrastructure, investment, technology, or economic resources.

• Political water scarcity: Access is restricted or distributed unequally through political institutions, territorial control, conflict, or unequal power.

  • Ex. DRC vs. West Bank vs. Qatar

Explain in words and a diagram the natural process(es) through which precipitation becomes groundwater and groundwater becomes surface water (e.g. a river)

• Rain comes down (precipitation)

• Hits ground:

  • Go over surface into river (runoff OR excess precipitation → rains more than ground can absorb)

  • Infiltrates into soil (infiltration)

    • Infiltrates to bedrock where water will not go through

      • Joins an aquifer, or a body of rock or sediment that is saturated with water

    • Moves with gravity, flowing into river

      • Return flow → water diverted for human use (ex. irrigation) that flows back into water system

      • Base flow → groundwater seeps into river, not water from human consumption

Explain with words and a diagram how the use of a well can cause surface water (e.g. a river) to become groundwater

• during the process of induced recharge, pumping from a well near a surface water body (such as a river, stream, or lake) lowers the local groundwater level

• This drop creates a hydraulic gradient—a difference in water pressure—that pulls or "induces" water to seep from the surface source through the riverbed or banks and into the aquifer

Explain with words and a diagram how a coastal city using groundwater can cause its aquifer to become saline

• Salt water and fresh water have different properties, they stay separate: Top fresh, bottom salt

• When a city pumps freshwater from its aquifer faster than it is replenished, seawater moves inland into the aquifer or rises toward pumping wells, a process known as saltwater intrusion

• Once the freshwater aquifer becomes saline, its water may no longer be usable for drinking or agriculture without treatment

• Doha stopped doing this, trying push salt water out by injecting it with treated water

Explain subsidence and its relevance to understanding the impact of sea level rise and storm surges on coastal flooding

• Groundwater extraction can cause land subsidence because removing groundwater reduces pressure in the spaces between underground sediment particles, so the ground compacts and sinks

• Problem = tapping groundwater at higher rates than can replenish

  • Once land sinks, aquifer cannot hold water again

  • Need to pump water deeper and deeper = need more energy

  • Take out groundwater at unequal rates around world = change Earth’s spin

• In coastal cities, this worsens flooding because the land surface is moving downward while sea levels may simultaneously be rising

  • Mexico City pumping out groundwater = city sinking, buildings tip

  • Ex. Jakarta sinking so much move capital → Borneo (connected to coastal land subsidence)

Be able to delineate a watershed using a topographic map, estimate its area and estimate the volume of water it generates per year if you are given average annual rainfall. This guy does a pretty good job of explaining the delineation approach.

Understand why I want you to be able to think about the relationship between basin area, annual precipitation, and water availability.

• A basin's area and annual precipitation determine how much water enters the system through rainfall and snowfall

• All else equal, a larger basin or one receiving more precipitation will collect more water

• However, this does not tell us how much water is actually available for human use because water can also be lost through evapotranspiration, discharged downstream, or stored

• A basin can receive large amounts of precipitation but still experience limited water access because of geography, infrastructure, political decisions, or unequal distribution.

For a given basin, be able to hypothesize the locations of water’s 1) function, 2) color [green, blue, grey], and 3) development timeline

• Connected to green, blue, grey water (look at slide with Walla Walla water basin)

• Water policy = everyone wants what benefits them = discussions go nowhere
  
  

Upper vs Lower Basin 

Upper	Lower Basin
produces runoff and provides upstream water supply	lower basin communities concentrate irrigation, urban use and other demand.
green water in soil and vegetation, blue water at the start of the stream	lower is blue water in river and canals, green water in agriculture, and grey water from domestic sources
Experience later development of certain infrastructure and resources	Contain older agriculture settlements and urban development

People upstream and downstream have different interests, and earlier development establishes infrastructure, legal rights, and expectations that shape later decisions.

Critique this statement: “The basin is the natural unit for water management”

• From a hydrological perspective, the basin is a natural unit of management because water within its boundaries is physically interconnected and drains toward a common outlet

• However, basins are not necessarily natural units of political organization

  • Global Water Partnership pushes countries to have a water policy based on the basin as the most important unit for management HOWEVER no countries are actually organized in this way

  • Pushes an ideal that does not work in practice

• Political boundaries, property rights, administrative agencies, and water laws rarely coincide with hydrological boundaries

• For example, the Aral Sea Basin was once governed within the Soviet Union but is now divided across several independent countries, creating conflicts between upstream hydropower generation and downstream agricultural irrigation

• Therefore, while a basin-based approach makes physical sense, it creates governance challenges

Know what a closed basin is and be able to critique a statement that somewhere is “running out” of water (read article)

• Out of water = build another dam (really = want more water than I have)

  • At some point, once all water is used, must focus on management

  • Closed basin = closed for additional development, nothing else that you can do

Know what these things are and their function/impact in terms of water management. Think about them also in terms of where they would fit in a water balance for Georgetown, the Potomac Basin and the U.S.

Feature	What it does	Impact on Water Balance
Trees/native plans	Intercepts precipitation, use water through transpiration, and help water infiltrate	Reduces and delays runoff, can increase ET
Permeable Pavers/asphalt	Allow precipitation to enter the ground instead of flowing directly into storm drains and to treatment facility	Increase infiltration and reduce surface run off
Leo’s	Uses water directly and indirectly through food production, 1000 L of water for 1 kilo of grain, huge virtual water footprint	Largest water consumption on campus is at Leo’s,
Powerplant	single largest user of energy on campus (cool/heat/move water around)	Connects water consumption and energy use
Rain gardens	Collect storm water, infiltration, plant uptake, and ET	Reduce and delay stormwater runoff
Roof top gardens	Causing water to stay on roof longer, water infiltrates slowly through soil + some water used by plants	decreases amount of water which makes it to water treatment facility
ICC Roof	Solar energy produces power without water	Reduce indirect water requirements for electricity generation

How would these things fit into a water balance/hydrological cycle? What do they do? Is it a good idea? Does it make sense to do this given the problem?

***water, food, energy closely connected – must always think about them together

For example, Georgetown's permeable pavers could be valuable even if they do not significantly reduce total basin-wide water consumption

Why?

• Because DC's water management problem involves stormwater arriving too quickly and overwhelming the combined sewer system

• The goal is therefore not necessarily to reduce all water use

  • It may be to change the timing and location of water flows

• This connects directly to your professor's first lecture: Water management is about extremes and variations, not averages

Be able to make a map of DC that shows the 3 major rivers, where our drinking water comes from, where it goes to and where it is supposed to go to, and the role of water as a socio-economic and racial boundary

• Supposed to go to Blue Plains Wastewater Treatment Plant,

  • In reality, dumped into river when it rains

  • DC has a combined sewer system in older parts of the city, meaning sewage and rainwater share the same pipes. During heavy rainfall, the system can become overwhelmed, resulting in combined sewer overflows that discharge diluted untreated sewage and stormwater into local waterways

Be able to use water balance thinking to explain situations similar to the class examples of the Colorado River, the Aral Sea and the Indus Basin Irrigation System (or similar). Be able to do this with diagrams and using the formal water balance equations similar to those from the Aral Sea homework and supplemental Aral Sea homework

• Water balance

  • ALWAYS balances (based on what you define as a system)

  • Think about system, then think about inputs/outputs

    • Water in - water out = change in storage

  • If you know some variables, you can find missing values by substitution

• Study 

  • Bathtub

  • Framework: is the water drawn out by evapotranspiration of trees or irrigation?

  • Pakistan case

Understand the two key approaches to surface water law in the U.S. and why they are applied where they are in terms of induced institutional innovation theory. Think also about the challenge of path dependency in an era of changing scarcity/abundance. Add in the challenges of applying law when there is groundwater/surface water, withdrawal/consumption and quality/quantity

• Riparian right still used in eastern United States, taken from British common law

  • Agriculture possible without irrigation

  • Right to use water = attribute attached to property rights for land (ex. own property with water running under it, automatically have right use some of water)

  • Reasonable use = cannot take all of water, can only use what is defined as reasonable (multifactor analysis)

    • If there is a shortage, the shortage is shared (works because a lot of precipitation = not a lot of water needed for irrigation, can reduce water proportionally and everyone has enough to get by – used for industrial/domestic/transportation)

• However, in western United States, prior appropriation was adopted because of the smaller amount of precipitation 

  • Agriculture not possible without irrigation

  • If share shortage = no one has enough water to get by (ex. for mining/agriculture)

  • Based on prior rights for gold mining: whoever was there first has first right to use whatever amount of water they need (“first in time is first in right”)

    • Older right = more senior, older right takes precedence in times of shortage

      • In times of shortage, person with first right can still use first allocation (though people with later rights might have no water)

    • Users must: divert water + put water to continuous beneficial use (cannot hoard more than you need for your uses)

    • Priority date: date water first put to beneficial use, determines seniority of right compared to all other uses

    • Forfeiture: for nonuse (use it or lose it)

• Thus, based on induced innovation theory, a change in relative resource endowment, the water in the environment, caused a legal innovation

  • There is not one water policy that works everywhere

• Induced institutional innovation theory = environment induces creation of institutions that work with that environment

• Path dependency

  • With the scarcity of water, path dependency becomes dangerous 

    • Societies become locked into specific ways of managing water, making it difficult to change course despite changes in abundance

• Groundwater

  • Not straightforward where groundwater law is applied and how

  • Historically, groundwater was not considered with water rights

  • Typically, groundwater and surface water are managed separately

• Withdrawal

  • E = biggest use rarely agriculture (because rainfall)

  • W = biggest use usually agriculture

• Quality/quantity

  • Get right to water = some quantity you can take out of river

    • Says nothing about quality of the water you got

    • Do you have a responsibility to return the water with some sort of quality

    • Agencies originating at different times with different purposes, lacks communication to ensure quality of water

    • Typically, quality and quantity managed separately

Understand the groundwater approaches

• Gaining stream (effluent) → stream gets water from groundwater

• Losing stream (influent) → river losing water to groundwater

  • Groundwater table below river, as water flows towards river some goes into river some continues underground (also happens when pumping too much groundwater with well)

• Groundwater = historically not considered with water laws

  • Absolute dominion/ownership: flows beneath property = your water (use as much as you want – race to the bottom)

    • TX, GA, CT

  • Reasonable use: analog of riparian rights for surface water (piece of land with groundwater beneath = right to reasonable use of groundwater on your property)

    • Cannot export elsewhere/reduce use proportionally during shortage

  • Correlative rights: same as reasonable use but right to export water

    • CA

  • Prior appropriation: first in right first in use (drill well first)

    • OR, WA, ID

Know how long and often has the supreme court been hearing surface and groundwater cases

• Not for very long and not very often

  • Water issues/the idea of scarcity and competition for water are relatively new (new era)

Be able to use the What, Where, Water framework to discuss water availability and access and critique typical water scarcity maps

• Access versus availability (not the same thing)

  • Water scarcity maps focus just on availability, not on who has access

    • Ex. DRC looks like has lots of water but in reality people have little access to clean water versus Qatar looks like has little water but in reality people have lots of access

Be able to explain induced innovation theory and what it suggests about the appropriateness of a given technology (or institution) in a particular place or under a particular set of conditions. In other words, if two places use two different technologies (or institutions), does it necessarily mean one is better/more advanced than the other?

• Induced innovation theory (demand pull)

  • Relative resource endowments determine what tech “works”

    • If endowments/prices change, tech change is “induced”

    • Ex. Japan adopted high yielding seeds before the US, because land was more scarce relative to labor

• A labor-intensive technology might make sense where labor is abundant and capital is scarce, while a capital-intensive system might be better where labor is expensive

• The key question is not which technology is most advanced, but which technology fits the local conditions and incentives

  • The same reasoning applies to institutions, including different water laws in the eastern and western United States