Lecture 1: Introduction to Watershed Planning / Management

water is the

basis for all life

Water defines the

physical landscape, limits human activity (population size and location, economic growth), and makes patterns in nature (vegetation and wildlife)

there is only how much freshwater in the world

2.5%

the demand of water is increasing—which means there is rising consumption—meanwhile the supply is remaining somewhat stable, this results in

an increasing gap between supply and demand of water

has water consumption and water withdrawals risen, dropped, or stayed the same compared to the human population?

water consumption and water withdrawals have risen

Water geopolitics are

Trade-offs between consumption and instream values, producing conflict (like Syria)

the basic water needs of many people

are not being met

as of 2025,

2 billion people lack access to clean water and 4.4 billion people lack clean water at home

the result of people lacking access to clean water is

250 million (2019 estimate) cases of water-related diseases, 3.5 million deaths each year, and > 1,000 children under 5 die every day on average

2.5 billion people rely on

groundwater supplies; in US - 38%

21 of 37 largest aquifers are being depleted worldwide, or in other words have

exceeded sustainability tipping points

some areas of Mexico City are

sinking at 1 inch per month

in Beijing, the water table has

dropped 1,000 feet since the 1970’s

Houston is the

fastest sinking major city in the US

What is subsidence?

the downward vertical movement of the Earth’s surface

Subsidence is due primarily to

ground water (GW) pumping, also oil extraction

subsidence causes major

damage to infrastructure (roads, buildings, underground pipelines; changes in drainage patterns; making some infrastructure obsolete)

Aquifer pores are the interconnected spaces within

the rock or sediment that allow groundwater to flow

Aquifer pores are drying up, which results in

compaction within the aquifer which is permanent damage (can’t hold as much water as before)

the inflow of water and the outflow of water are

not balanced

Aquifer water turns over much more

slowly than most other water pools

rates of turnover for aquifer water can be

100s to 1,000’s of years (the range in turnover rate is large)

what is Fossil Water?

an aquifer not actively being recharged, they are nonrenewable

more than 75% of groundwater

is nonrenewable

it is critical for water management and policy to have a clear distinction

and identification between renewable and non-renewable water tables

renewable aquifers depend on

current rainfall for recharge

in Edward’s Aquifer, pumping has increased

4x since the 1930s, and at times now exceeds annual recharge rates

increased water withdrawal makes aquifers more susceptible to

climatic changes and contamination - like saltwater intrusion

links between surface and ground waters are most important in regions

with low rainfall (like arid and semi-arid regions) (33% of earth’s surface, 20% of global population-primary source of water for drinking and irrigation)

in areas of low rainfall, results are

limited in opportunities for aquifer recharge, and are highly susceptible to depletion

the water footprint of a product contains the sum of

the volume of freshwater used for production (water consumed + water polluted throughout the supply chain)

does it cost more to pump groundwater or use rain to irrigate cropland?

cost more to pump groundwater, rain = free

what are the order of categories that use land in the US from least to greatest?

Miscellaneous — cemeteries, golf courses, areas of “low economic value like marshes or deserts” — (3.6%)

Urban (3.7%)

Special Use—national parks, wildlife areas, highways, railroads, military bases (8.9%)

Cropland (20.7%)

Forest (28.5%)

Pasture/Range (34.6%)

what is the current rate of change?

an increase in urban area of 1,000,000 acres per year (area of Los Angeles, Houston, and Phoenix combined)

why do we care about the California drought?

$35 billion in agricultural revenue – most productive in US

70% of US-produced fruits and nuts

55% of vegetables

22% of milk and cream

Nation’s sole producer of a dozen crops

State employs 27% of all farm workers in the US

what are the different variable resources for water

variable in space, variable in time, variable in quality

what are the different variables in space?

variations over large or small distances, globally, regionally, locally

what are different variables in time

duration, frequency, amounts, hourly, daily, monthly, seasonally, annually, cycles

what are different variables in quality

sediments, contaminants, natural state

Precipitation: Local Spatial Variability - Goliad, Texas example

Goliad, Texas ​

• Two stations located about one mile apart​

• One in Goliad ​

• The other about 1 mile SE of town​

37 years between 1950 and 2004 ​

• Average annual rainfall in Goliad is 35.80 inches ​

• Average at the station 1 mile SE of Goliad is 32.19 inches ​

Mean annual rainfall at the Goliad 1SE location is more similar to mean annual rainfall at Beeville (31.13 inches) 31 miles southwest of the Goliad 1SE location than it is to the Goliad station 1 mile north.​

List the three water resource problems

Problems of absolute supply (quantity)

Problems of regimen (timing)

Problems of quality

Solutions for Absolute Supply Problems (Quantity)

1) Importation of water from an area in which a surplus occurs naturally. ​

2) Weather modifications - rain-making or cloud seeding​

3) Desalinization of Brackish Water ​

4) Reduction of evapotranspiration losses​

Explain the importation of water from an area in which a surplus occurs naturally

One of the oldest solutions used by man (Roman Aqueducts). ​

Many present-day examples: ​

• Texas Water Import Plan- 1970’s​

• Lake Alan Henry​

• Owens Valley, CA​

  • Provide drinking water to Los Angeles​

    • Year Completed 1913 ​

    • Construction Duration 5 years ​

    • Aqueduct Capacity 485 cfs ​(cubic feet per second)

    • Construction Cost < $23million ($1.5 billion in today’s money)​

    • Total Length of Aqueduct ~233 miles​

  • Drained Owens Lake dry​

    • Left a salt flat​

    • Now have a problem with dust storms

  • Pumping ground water​

    • Mojave Desert – 4” of rainfall average in some places​

    • Ample groundwater from runoff off Sierra Nevada Mountains​

    • Led to significant legal issues with residents​

• Lubbock, Texas

  • Prior to 2011​

    • Majority of water from Lake Meredith​

  • In 2011​

    • Voters approved 16% rate increase on water bills​

    • 50-mile pipeline and water treatment system​

  • Drawing water from Lake Alan Henry in 2013​

  • Today​

    • Most water comes from Lake Alan Henry​

    • GW from Bailey and Roberts Counties​

    • ...a bit from Lake Meredith​

Weather modifications - rain-making or cloud seeding​

Spread chemicals​

• Silver iodide, potassium iodide, dry ice, table salt​

• Done by aircraft or dispersion devices on the ground​

Studies have produced mixed results​

Concern about the chemicals​

• Do occur in low concentrations​

• Concern regarding sensitive wildlife species ​

2008 Summer Olympics in Beijing​

• Tried to prevent rain clouds from reaching Beijing during the opening and closing ceremonies​

**NOT currently a viable solution​

Desalinization of Brackish Water ​

Not practical​

Expensive ​

• $1.32 to $4.27 per 1000 gallons just for desalinization​

  • Lower cost – treatment of brackish water​

  • Higher cost – treatment of seawater​

• Additional costs for piping of water ​

• Translates to $429-$1390 per acre-foot​

  • Too expensive for irrigation​

Saudi Arabia​

• 30 facilities​

  • Produce 11.5 million cubic meters / day​

  • 1.5 million barrels of oil / day​

• Solar power instead​

  • Currently at 120 megawatts​

  • Slated to grow to 770 megawatts​

• Costs?​

  • Riyadh – capital city​

    • Currently requires 1.6 million cubic meters / day​

    • Expected - 6 million cubic meters / day by 2030​

    • Cost – do or die…​

Australia​

• All energy produced by solar​

• Produce grown hydroponically in one location​

• Shipped across the continent​

Reduction of evapotranspiration losses​

Reduce the amount of energy available for vaporization of water​

Examples​

• Lining canals – increase velocity, reduce evaporation losses​

• Shading channels with vegetation - cooling​

• Wind breaks​

• Use of black “shade balls”​

  • Millions of black balls floating on surface​

  • Reduce solar radiation reaching the water​

  • Lower temperature​

  • Black vs. white – reduce UV absorption causing formation of carcinogenic bromate​

Solar panels over canals​

• Reduce losses due to evaporation​

• Cooling of panels, so operate more efficiently​

what are the problems of regimen (timing)

1) Solutions to High Flows​

2) Solutions to Low Flows​

what are the solutions to high flows?

Otherwise known as “Flooding”​

Increase channel capacity to handle excess flows​

Decrease volume of flow so it does not exceed channel capacity​

Remember: both high and low flows are natural!​

Benefits to high flows?​

• Some desert riparian vegetation requires flooding to clear away debris and allow for germination and optimal production

describe the 2019 floods in the midwest

Over $3 billion in damages​

• $1.6 billion in Iowa​

• $1.3 billion in Nebraska​

3 deaths​

describe the 2013 floods in colorado

100-year storm in mountainous terrain​

Over $2 billion in damages​

2000 homes destroyed, 17,500 homes damaged​

200 miles of roads and 50 bridges damaged​

what are some solutions to low flows?

Need storage and regulation to give even flow​

• Dams and reservoirs ​

Evaporation is chief cause of losses​

list the problems of water quality:

No simple solution exists!​

Options​

• When water is naturally unsuitable for use​

  • Develop a different source​

  • Treat to make usable​

• With anthropogenic unsuitability​

  • Careful use of lands and potential polluting agents​

  • Treatment of wastes prior to discharge into streams​

  • Modification of waste disposal to take advantage of natural conditions

definition of a watershed:

an area of land drained by (or which sheds its water into) a stream or river system​

• Synonymous with “catchment” or “drainage basin”​

management refers to what?

the act, art or manner of managing, controlling, directing, etc.

Watershed Management Defined

The management of land for the “optimum” production of high-quality water, the regulation of water yields and for maximum soil stability, along with other products of the land.​

list the three principal aspects, or ingredients, of watershed management

water, land (or landscape), manipulation (or management)

objectives of watershed management

Maintain and / or increase water yields

Maintain and / or improve water quality

Regulate timing of stream flow

Control excessive soil erosion and excessive runoff

• Excessive implies man-induced

historical development of watershed management

1342​

• First known governmental action for watershed protection​

• Establishment of a “forest preserve” in Switzerland​

1833​

• First action in the US​

• New York – created the Adirondack Forest Preserve​

• “to protect the headwaters of the chief rivers of the state” ​

1890​

• Congressional appropriations for rain making experiments​

1908​

• Arizona – first forest experiment station ​

Many additional “simplistic” attempts​

Only in last 30 years have studies become more extensive and scientifically rigorous​

Decision to do nothing is still a decision​

​1910​

• Wagon Wheel Gap, Colorado​

• Classic watershed experiment​

  • Paired watersheds in Rio Grande Basin​

  • Installed gauges for precipitation and stream flow​

  • Clearcut one of the watersheds in 1919​

  • Saw increases ​

    • Runoff – max daily, high-flow volumes, average annual yield​

    • Erosion ​