arrosage automatique

Oklahoma Water Survey

The Oklahoma Water Survey will collect, analyze, interpret and disseminate research-based information about the state’s water resources to researchers, students, teachers, citizens, governments, businesses and organizations.


Oklahoma Defends Its Softball Title - New York Times June 7, 2017
Rodd Moesel: Keep planting, but keep up with watering - June 3, 2017
US Department of Commerce invests $1.5M for water infrastructure improvements in Oklahoma - WaterWorld May 23, 2017
Flooding rainfall closes roads, prompts water rescues in central US - May 20, 2017
Grant funds water system upgrades - Examiner Enterprise May 18, 2017
OKC Sustains Damage To Water Pump Station, Power Lines - KWTV May 17, 2017
Trump Administration Will Invest $23.6 Million in ... - Triple Pundit - Triple Pundit (registration) (blog) May 15, 2017
Tap Water Taste A Bitter Issue For OKC Downtown - KWTV May 11, 2017
OK considers selling water to TX to help fill the budget hole - KSWO May 10, 2017
Oklahoma awarded $855000 to protect water quality - WaterWorld May 10, 2017

Water Conservation in Oklahoma: It’s never too late!

By Dr. Robert W. Puls, Director
Oklahoma Water Survey
Norman, Oklahoma

Some water Facts:

  1. The earth is covered with water but only about 3% is fresh water, meaning drinkable or potable
  2. Of that 3%, 2% is tied up in snow and ice
  3. The remaining 1 % is in lakes, reservoirs, rivers, wetlands, and ground water
  4. 7,000 years ago, water shortages spurred humans to invent irrigation
  5. Fresh water withdrawals have tripled over the last 50 years
    1. Population growth
    2. Consumption increase
    3. Energy demands
  6. USGS estimates for 2005 indicated 41.5% and 37% of water uses were for thermoelectric power and irrigation and 8.5% for domestic use.
  7. Water on earth is finite and constant. We have the same amount today that we had thousands of years ago, but reductions in fresh water can occur due to water contamination.
  8. Current domestic water use per person per day ranges from 60 to 180 gallons in the US ( with less per capita usage in the east and more in the west. Oklahomans use about 80-100 gallons per day.
  9. Population growth in Oklahoma is projected to increase from approximately 3.7 million to 4.8 million by 2060 (OCWP, 2012)

Figure 1. EPA estimates the following breakdown for domestic water usage.

The Water Cycle

The water cycle or hydrologic cycle on earth involves the continuous arrosage automatique of water via evaporation, condensation, precipitation, movement over the land surface and infiltration. Water evaporates from the oceans and other open water bodies, moves across sky as water vapor in clouds, condenses and returns to earth as rain and snow, and then returns to the oceans and other open water bodies through rivers and underground pathways to start the cycle again. Some of the water that falls on the land evaporates from the soil or is transpired from plants back into the atmosphere. Water flows overland to stream channels, lakes, or the sea. Water infiltrates through soils and then resides in an unsaturated zone where it exists or in a saturated zone. It is this latter component that is referred to as ground water.

Oklahoma’s Water Needs

Like most locations, Oklahoma’s demands for water will increase as population increases. The Oklahoma Comprehensive Water Plan (OCWP), 2012, projects about a 28% increase in water demand for the state by 2060 (Figure 2). The state legislature passed the ‘Water Act for 2060’ in 2012. This law establishes a statewide goal of consuming no more water in 2060 than is consumed now. To achieve this goal, we must use our existing supplies more efficiently, find new supplies and establish more efficient infrastructure to limit leakage and waste. Increased conservation and efficient use and water management practices will be essential to realizing this goal.

Figure 2. Water demand projections for different use sectors for Oklahoma

In response to the pressures of population increases and urban growth together with the potential for more severe and more frequent droughts, it is increasingly challenging to solve our water supply needs. Developing new water sources and interbasin water transfers is one approach, but alleviating demand may be more cost effective. This can be done through conservation, recycling and reuse.

Clearly the largest users of water are the agricultural and municipal/industrial sectors, however the growth rate would appear to be greatest for the oil and gas and thermoelectric power sectors. The good news is that these two sectors could make use of alternative sources of water to satisfy their needs. Non-fresh water sources (>5000 total dissolved solids [TDS]) or marginal waters could be used. Ground waters of over 5000 TDS do not require a permit for withdrawal in Oklahoma. There would be no competition between agricultural uses and municipal and rural drinking water supplies. Movement in this direction is already happening. Oil and gas industries in Oklahoma and elsewhere are increasingly using recycled or other marginal water sources in their operations. This is a relatively new practice but one that should be encouraged. Likewise, power plants are turning to marginal water sources for cooling needs (e.g., Luther and Newcastle, OK).

Reductions in potable water usage in agriculture and municipal/industrial sectors can also be achieved via reuse strategies. While the Oklahoma Water Act for 2060 addresses the general issue of conservation, it is noteworthy that the Oklahoma Department of Environmental Quality (DEQ) recently promulgated specific guidance for water reuse in 2012 ( In Title 252, Chapter 627, DEQ defines “Reclaimed water” as wastewater that has gone through various treatment processes to meet specific water quality criteria with the intent of being used in a beneficial manner. The Guidelines establish five categories and outlines permitted uses for all but category 1. Such water can be used for irrigation of golf courses, public use areas (e.g. sports complexes), toilet and urinal flushing systems, irrigation of livestock pastures, subsurface irrigation of orchards and vineyards, and restricted access landscape irrigation to name a few of the beneficial uses. There is no mention of potential reuse of treated wastewater for indirect potable water supplies; presumably this is restricted to category1.

Some states now allow reuse for indirect potable water supplies under certain restrictions and conditions. As might be expected, these are areas of the U.S. experiencing serious water supply shortages. Treated municipal wastewater is of a much higher quality than it was 20-30 years ago and often superior to the quality of the rivers and streams where it is discharged. The North Texas Municipal Water District (NTMWD) diverts return flows from the East Fork of the Trinity River, contributed by NTMWD-owned or customer-operated wastewater treatment facilities through a constructed wetland prior to delivery to Lavon Lake for subsequent treatment for drinking water use.

Water Conservation and Leaks

As Figure 1 illustrates almost 14% of domestic water usage is lost to leaks. Recent studies have shown that typically a small number of homes are responsible for the majority of the leakage: 105 of the homes were responsible for 58% of the leaks found ( Obviously this has implications for the water bills for those homes. The use of water monitoring devices on supply pipes would help identify these leakers. It should also be possible to identify these homes based on historical trends in water usage by either the homeowner or the utility.

Water losses also can be significant in public supply systems, particularly those with aging infrastructure. It is estimated that 7 billion gallons per day across the country are wasted due to leaking pipes (American Society Civil Engineers, EPA). This is treated water that costs about $2.6 billion per year. 30% of pipes in systems serving more than 100,000 people are between 40 and 80 years old. This aging infrastructure problem is ubiquitous regardless of regional location. Some areas are worse off due to age (Midwest, Northeast). The longer we wait to address this issue the more it will cost.

A recent report by the American Society of Civil Engineers (ASCE) found that improvements for aging water infrastructure could cost U.S. businesses $147 billion over the next decade. The report identified the following business sectors as absorbing the brunt of the impact: retail, restaurants and bars, and construction businesses. These economic impacts could be reduced if households and businesses adopt more sustainable approaches to water usage and management.

Water Conservation and Equipment Changes

As indicated above, toilets are a major drain on our water usage. First, why are we even using treated potable water to flush our toilets? Captured rainwater and other sources or non-potable water would do the job just fine. Older toilets, those most commonly used, require 3-5 gallons per flush. New, low flush toilets use than 2 gallons. Many communities now require these more efficient toilets in new homes and buildings. Clothes washers are also heavy users of potable water requiring 40 gallons per load; newer ones use than 25 gallons. There are also restricted flow faucets and showerheads available that can save water. Many cities provide ‘conservation kits’ for minimal cost to address some of these changes.

Other ways to save water include taking showers instead of baths, taking shorter showers, running dishwashers and clothes washers only when completely full, and capturing rain water for gardening and lawn irrigation. Many communities have programs to provide rain barrels at cost or low cost (

Water Conservation and Landscaping

There are a number of turfgrass varieties available that need less water or are drought tolerant. Perhaps as important as choosing the right variety of grass to conserve water is the strategic placement of turf, irrigation systems, and hard impervious surfaces. Systems should be designed to avoid watering of hard surfaces, thus losing valuable water to runoff and storm drains. For existing irrigation systems, yearly adjustments are recommended to avoid watering hard surfaces. Sensors are available so that irrigation does not occur during rainfall events. Texas A&M University ( has produced a guide to a ‘WaterWise Landscape’. It involves the following seven principles:

Appropriate plant selection

Planning and design
Soil preparation
Practical turf areas
Efficient irrigation
Use of mulches
Appropriate maintenance
Xeriscape is a term that applies to low-maintenance landscapes requiring less water. These are water-efficient landscapes that can be designed according to local geographic and climatic conditions. The use of native plants is not necessary but certainly worthy of consideration. Oklahoma State University maintains a site ( that provides a listing of different xeriscape plants including trees, shrubs, groundcovers and grasses. Xeriscape is gaining in popularity as certain regions that increasingly experience drought conditions and communities face mandatory watering restrictions.

The Path Forward
It is not too late to begin planning for a future more dependent than ever on water but having less fresh water than we have grown accustomed to having. Conservation of the water we have will need to play a larger role in meeting our future needs. To make this work, we need to change our current thinking about the value of our water resources and how we conserve and efficiently use those resources and make changes to our laws and management strategies to more effectively meet this challenge.

Water Reuse Forums

B.Puls Forum Series Introduction
D.Smithee Water Quality/Quantity Management
C.Parrott Water Reuse Policy And Regulations
D. Sabatini Water, WaTER and H2O
M. Rickman East Fork Raw Water Supply

Oklahoma Water Survey Newsletter

Water Resilient Communities

Resilience is the capacity to maintain functionality in the event of a
disturbance or disaster. Events such as floods, droughts, hurricanes
and tornados are examples of such disturbances. While disaster
recovery plans provide a road map on how to respond to such
disturbances, they are not in and of themselves sufficient to build
long-term resilience. Building a resilient community requires
longer-term planning, new approaches to community infrastructure
development, and integrative management of supplied services
among all community users.
One simple definition for Drought is a protracted period of deficient
precipitation. Other definitions are more operational in nature and
take into account other climatic variables. In Oklahoma drought is a
common threat to communities. Drought is a relatively slow moving
disaster that tends to fly under the radar for most people until it
impacts them directly creating concern and maybe panic until the
drought ends. Impacts are often regional or statewide and can be of
significant duration. Since we know that such events have occurred
with some regularity here in Oklahoma, it is essential that we build in
resilience to their effects to ensure the sustainability of public and
environmental health.

Comprehensive Water Plan, the public policy of this state is to
establish and work toward a goal of consuming no more fresh water in
the year 2060 than is consumed statewide in the year 2012, while
continuing to grow the population and economy of the state and to
achieve this goal through utilizing existing water supplies more
efficiently and expanding the use of alternatives such as wastewater,
brackish water, and other nonpotable supplies.”A ‘Water for 2060
Advisory Council’ was created by the Act. This Council has met several
times and notes for these meetings are available on the Oklahoma
Water Resources Board website. The Advisory Council is scheduled to
submit an Advisory Council Report to the Governor and the Legislature
in the second half of 2015. A series of public meetings of the Advisory
Council were held in March-April 2014 and focused on “Hot Spot”
basins that are projected to have the most significant water supply
challenges within the next 50 years. These discussions centered
around 4 major regions in the state: the Panhandle, the Southwest,
Beaver-Cache and Lower Washita, and the Central Watershed region
tSummary.pdf ).
The Oklahoma ‘Water for 2060 Act’
55%20ENR.PDF) states “in order to protect Oklahoma citizens from
increased water supply shortages and groundwater depletions by the
year 2060 in most of the eighty-two watershed planning basins in the
state as described in the 2012 Update of the Oklahoma
In reviewing the summaries of the meetings, it was interesting to note
the common recommendations that emerged for the different
regional discussions. These included the following:
• Incentives to increase wastewater reuse for potable and other
water supply needs
• Investigate uses of brackish groundwater as opposed to fresh
• Education of the public on different aspects of conservation and
reuse strategies
• Improvements to reduce irrigation and storm water runoff
Water Resilient Communities 1-2
Education, Research, Outreach on Water Issues
Upcoming Water Resources Meeting 2
Oklahoma Water Survey Education, Research, Outreach on Water Issues
Upcoming Water Resources Meeting

All of these recommendations are also discussed at length in the 2012 Oklahoma Comprehensive Water
Plan. Wastewater reuse is actively being considered in many Oklahoma communities, but policies need to
be enacted to establish a clear pathway to gain approval to augment drinking water supplies while still
protecting public health. Education of the public on this issue is essential and the Oklahoma Water Survey
(OWS) and University of Oklahoma faculty are working with the Oklahoma Water Resources Board, the
Department of Environmental Quality and other key stakeholders to provide public forums on this issue in
The oil and gas industry in the state is looking at the use of brackish water for their operations but
more characterization research is needed to identify the extent and quality of these water sources to accelerate their use. Reduction and storage of agricultural and municipal runoff can reduce sedimentation into
our reservoirs and increase recharge of aquifers and thus augment water supplies. The use of green
infrastructure has been used to a limited extent in Oklahoma to replace or expand on our existing aging
gray (pipes, culverts etc.) infrastructure. Incorporation of green infrastructure can, for newly developed
urban and suburban areas, reduce runoff and keep rainwater where it falls rather than sending it downstream via pipes and culverts.
These all represent strategies that would increase water resilience in the face of natural disasters and
climate change. They also require an increased need for education and outreach on these topics to gain
public acceptance and promote long-term investment in water conservation and reuse practices that have
not been widely adopted in Oklahoma. There continues to be a need to develop better integrative water
management programs among different state agencies and among key stakeholders at the state, watershed and local level.
Previous OWS Newsletters have touched on some of these topics
Green Infrastructure: Facts and Benefits
Water Resilient Communities

Sustainable Water Management Conference
Mar 15 - 18, 2015 - Portland, Oregon
2015 NGWA Groundwater Summit
March 16 - 18, 2015 - San Antonio, Texas
2015 WQA Aquatech USA
April 21 - 24, 2015 - Las Vegas, Nevada
World Environmental & Water Resources Congress
May 17 - 21, 2015 - Austin, Texas
Water Summit 2015
Jun 23 - 24, 2015 - Portland, Oregon
NGWA Upper Great Plains Groundwater Conference
Sep 22 - 23, 2015 - Cheyenne, Wyoming
2015 Water Environment Federation’s Annual Technical Exhibition and Conference
Sep 26 - 30, 2015 - Chicago, Illinois
2015 NGWA Conference on Groundwater in Fractured Rock
Sep 28 - 29, 2015 - Burlington, Vermont

Green Infrastructure: Facts and Benefits


Large paved surfaces keep rain from infiltrating the soil and recharging groundwater supplies. Impervious surfaces like streets, parking lots, sidewalks, and rooftops transport stormwater in volumes up to 16 times higher than natural areas1. This stormwater runoff delivers pollutants from motor oil, lawn chemicals, sediments, and pet waste to streams, rivers, and lakes untreated. Higher flows can also cause erosion and flooding that can damage property, infrastructure, and wildlife habitat.

In 2008 the EPA reported the total wastewater and stormwater infrastructure maintenance and repair needs for the United States to be $298.1 billion2. Conventional stormwater infrastructure or gray infrastructure is largely designed to move stormwater away from urban areas through pipes and other man-made conduits. A potentially less expensive but effective alternative, green infrastructure uses natural processes to reduce and treat stormwater in place by soaking up and storing water. These systems provide many environmental, social, and economic benefits that promote urban livability and add to the bottom line.


Green infrastructure techniques use vegetation, soils, and natural processes to manage stormwater and generate healthier urban environments. Green infrastructure systems mimic natural hydrology to take advantage of interception, evapotranspiration, and infiltration of stormwater runoff at its source thus disconnecting impervious surfaces from gray infrastructure. This approach provides multiple benefits of flood protection, cleaner air, and cleaner water.

Green Infrastructure Techniques

Downspout Disconnection – the rerouting of rooftop drainage pipes to permeable areas, rain barrels, or cisterns. This allows stormwater to infiltrate into the soil and/or stores stormwater for later use
Rainwater Harvesting – systems that collect and store rainfall for later use. These systems provide a renewable water supply and can slow and reduce runoff. Such systems can reduce demands on increasingly limited water supplies in arid regions
Rain Gardens – also known as bioretention or bioinfiltration cells, these are shallow, vegetated basins that collect and absorb runoff by infiltration and evapotranspiration. Rain gardens can easily be installed in many unpaved spaces.
Planter Boxes – structures with vertical walls and open or closed bottoms filled with gravel, soil and vegetation that collect and absorb runoff. Planter boxes are ideal for space-limited sites in dense urban areas.
Bioswales – broad and shallow vegetated, mulched, or xeriscaped channels that provide stormwater treatment and retention. Bioswales slow water flow and allow infiltration into soils, thereby filtering stormwater flows. As linear features, they are appropriate along streets and parking lots.
Permeable Pavements – porous paved surfaces that allow rain to permeate into soils. Permeable pavements can be constructed from various materials such as pervious concrete, porous asphalt, permeable interlocking pavers.
Green Streets and Alleys – transform impervious streets into landscaped green spaces by integrating green infrastructure elements such as bioswales, planter boxes, and trees into street and alley design. Green streets and alleys are designed to store, infiltrate, and evapotranspire stormwater while adding to the aesthetics of landsapes.
Green Parking – integrate green infrastructure elements such aspermeable pavements and rain gardens into parking lot designs. Such structures manage stormwater on site, mitigate urban heat islands, and create a more pedestrian-accessible environment.
Green Roofs – roofs covered with growing media and vegetation. Green roofs are cost effective in dense urban areas or where stormwater management costs may be high.
Urban Tree Canopy- Trees intercept rain in their leaves and branches thereby reducing and slowing stormwater runoff. Homeowners, businesses, and cities can all participate in the planting and maintenance of trees.
Land Conservation – Open spaces and natural areas within and adjacent to cities can protect water quality, mitigate flooding impacts, and provide recreation. Important natural areas that help protect water quality and mitigate flooding include riparian areas, wetlands, and steep hillsides where construction may exacerbate erosion.

Oklahoma is facing population growth, land use change, aging infrastructure, and climate change2. All of these factors will increase demands for good quality water to be used in the public water supply, protection of fish, shellfish, and wildlife, as well as recreational, agricultural, industrial, energy exploration, and navigational purposes3.

Oklahoma Water Facts4

Oklahoma has approximately 55,646 miles of shoreline along lakes and ponds.
Oklahoma contains approximately 1,401 sq miles of water area in its lakes and ponds.
The majority of the state’s surface water (approximately 54%) is used for public water supply.
Groundwater accounts for 73% of total Oklahoma irrigation water use.
OCWP5 estimates approximately $44 billion (in 2010 dollars) will be required to meet the wastewater infrastructure needs for the next 50 years.

Conventional gray stormwater infrastructure is designed mainly to move urban stormwater away from urban environments, but green infrastructure reduces and treats stormwater in place while delivering environmental, social, and economic benefits. Here’s how:

Water Quality: by soaking up and storing water in place, green infrastructure reduces stormwater discharges. Lower stormwater volumes means reduced gray infrastructure overflows and lower pollutant loads. Infiltration and storage of stormwater can also help remove pollutants.

Flooding: Slowing and reducing stormwater discharges and peak flows can mitigate flood risk.

Water supply: Rainwater harvesting and practices that increase infiltration can provide a renewable, water supply alternative. Harvested rainwater can be used for outdoor irrigation and certain indoor uses thereby significantly reducing municipal water use. Water infiltration practices also recharge groundwater, an important source of drinking water.

Private and Public Cost Savings: Incorporation of green infrastructure into stormwater management systems can lower capital costs. Lower costs for site grading, paving, and landscaping, and smaller or eliminated piping and detention facilities provide savings for developers. In cities with combined waste and stormwater sewer systems, green infrastructure control measures can cost less than conventional controls, and green-gray approaches can reduce stormwater infrastructure costs.


Case studies have shown that, in the vast majority of the cases, implementing well-chosen green infrastructure practices saves money for developers, property owners, and communities while protecting and restoring water quality6. For example, the Gap Creek subdivision in Sherwood, Arkansas was redesigned to include green infrastructure elements. In this project open space was increased from 1.5 acres to 23.5 acres, lots sold for $3,000 more and cost $4,800 less to develop, resulting in $2.2 million in additional profit for the developer.6

Examples of Economic Benefits7:

• Reduce flooding – a reduction in flooding can increase property values in floodplains by up to 5%.

• Improved water quality – can increase market value by 15% for properties near lakes, rivers, streams, or coastal areas.

• Reduced filtration costs – along the Anacostia River in Washington, DC, bioretention methods saved $250,000 over the use of piped stormwater and sand filters.

• Infrastructure cost savings – replacing curb, gutter, and storm sewers with roadside bioswales saved one developer $70,000 per mile.

• Increased property values – lots in green infrastructure neighborhoods sold for $3000 more than lots using conventional stormwater infrastructure

• Protecting water quality – green infrastructure helps maintain clean water, which is usually less expensive than cleaning contaminated water. Not having to clean contaminated water is an avoided cost.

Table 1. Adapted Summary of Cost Comparisons between
Conventional and Green Infrastructure Approaches.6

Project Conventional Costs Green Infrastructure Costs Percent Difference
Gap Creek $4,620,600 $3,942,100 15%
Garden Valley $324,400 $260,700 20%
Kensington Estates $765,700 $1,502,900 -96%
Laurel Springs $1,654,021 $1,149,552 30%
Somerset $2,456,843 $1,671,461 32%

Green infrastructure is an approach that communities can choose to maintain water quality, provide environmental and social benefits, and support sustainable communities. Unlike gray stormwater infrastructure, which uses pipes and other man-made conduits to dispose of rainwater, green infrastructure uses vegetation and soil to manage rainwater in place. By regenerating natural processes in the urban environment, green infrastructure provides not only stormwater management, but also flood mitigation, lower infrastructure costs, increased property values, and improved urban livability.

Oklahoma is facing greater demands for water quality and supply at a time when stormwater infrastructure needs replacement or repair. In these tough and uncertain economic times, we need resilient, flexible and affordable solutions that satisfy several objectives at once. Green infrastructure is one solution.


Green infrastructure information, general benefits, and summary were adapted from:

*This website contains most links to PDFs cited in this document as well as much more information and resources.

1 Schueler, T. 1995. The importance of imperviousness. Watershed Protection Techniques 1(3):100-111.

2 State of Oklahoma Water Resources Board. 2011. Oklahoma Comprehensive Water Plan 2012 Update: Water Demand Forecast Report.

3 State of Oklahoma Water Resources Board.(Viewed 2012, June 20) Fact Sheet: Water Quality Standards.

4 State of Oklahoma Water Resources Board. (Viewed 2012, June 20). “Oklahoma Water Facts”.

5 State of Oklahoma Water Resources Board. 2012. Oklahoma Comprehensive Water Plan 2012 Update: Wastewater Infrastructure Needs Assessment by Region.

6 USEPA. 2007. Reducing Stormwater Costs through Low Impact Development (LID) Strategies and Practices EPA 841-F-07-006:

7 NC State University, A&T State University Cooperative Extension (Viewed 2012, June 20). Low Impact Development – an economic fact sheet:

“The Value of Green Infrastructure” document from American Rivers provides a framework to help communities measure and value the air quality, energy use, and many other benefits that green infrastructure provides.

Low Impact Development: A Design Manual for Urban Areas introduces general audiences to designing landscapes for urban stormwater runoff—a primary source of watershed pollution.

The Green Values® Stormwater Toolbox was developed primarily for use by planners, engineers and other municipal staff and provides tools to learn how the use of green infrastructure saves money and understand the costs and benefits of using green infrastructure to mitigate the need for different types of built water infrastructure, such as sewers and detention basins. This includes two easy to use stormwater management calculators.

Contact for More Information:

Shannon Schechter, NRC, RSKERC, Ada, OK; 580-436-8987,
Paul Mayer, US EPA, RSKERC, Ada, OK; 580-436-8647,


This article has not been subjected to internal policy review of the U.S. EPA. Therefore, the research results do not necessarily reflect the views of the Agency or its policies.

Water Quality and Total Maximum Daily Loads (TMDLs)

By Dr. Paul Risser
University of Oklahoma
and Dr. Robert Puls
Oklahoma Water Survey

The Total Maximum Daily Load (TMDL) is a calculation of the maximum amount of a pollutant a water body (for example, Oklahoma’s lakes, rivers or streams) can receive and still meet the applicable water quality standard. The TMDL calculation, which is a detailed process requiring data and mathematical models, is based on both the properties of the water body itself and the pollutant sources leading to a water body’s failure to meet applicable water standards. The calculated TMDL is then used to describe the necessary reduction in pollutants or changes in land management to reduce the pollutant to acceptable levels. This information is used as the basis for a plan to ensure that the water quality is restored. Through the work of the Oklahoma Department of Environmental Quality, Oklahoma has conducted TMDL studies of several basins and has plans to complete many more.


For many years the U.S. Environmental Protection Agency (USEPA) and state water quality agencies across the country have used TMDLs in implementing the Clean Water Act by establishing maximum pollution limits for industrial wastewater discharges (point sources). In the last two decades TMDLs have been widely applied to both point sources and non-point sources within watersheds.

The Oklahoma Department of Environmental Quality, Water Quality Division, Watershed Planning Division, has produced the detailed Oklahoma Total Maximum Daily Load Practitioners Guide ( along with a more general explanatory pamphlet (


The Total Maximum Daily Load (TMDL) is a regulatory term from the U.S. Clean Water Act (CWA) of 1972. Water bodies that do not meet applicable water standards with best practice technology-based controls are placed on the section 303d list (based on section 303d of the Clean Water Act) and as a result of that designation, require development of a Total Maximum Daily Load (TMDL) calculation.

TMDLs are developed in the context of a watershed, including the quality of the water in the water body or bodies, the water that flows into and through the watershed and the point and non-point sources of pollution. The general steps are listed below.

Define Watershed Goals – Describe the study area and spatial boundaries; define water quality standards; address key issues such as characterization of the impairment with respect to water quality standards; seasonal variability of concentration of water quality constituents; relationship between observed concentration of water quality constituents and flow; definition of long-term trends of constituents; existing permit limits for point sources within the study area; other general descriptive or background information and identification of the water quality monitoring stations.
Complete Watershed Assessment to define water quality targets (or TMDL endpoints) – Develop the field sampling plan (including quality assurance and quality control protocols) for describing the type, magnitude and location of sources of pollutant loading and loading conditions for point sources, nonpoint sources, background contributions, tributaries, and any upstream flows; selecting appropriate data and mathematical models for estimating water flows, sediment dynamics and pollutants from point and non-point sources.
Quantify loading and allocations – Use data to decide the data sources and time steps for analyses; calibrating and validating hydrologic, sediment and water quality models; estimating future growth in pollutant sources, where applicable; and deciding upon the numerical margin of safety to be used in the analyses.
Develop TMDL – Conduct the calculation for pollutant loadings as described in the next section.
Plan monitoring – Develop a plan for monitoring the water body in the context of the watershed as defined by the point and non-point pollutant loadings.
Plan implementation – Implement best practice managements and describe the watershed plan so the water body will meet the applicable water quality standards.
The TMDL for a water body, the Maximum Load Capacity, includes four components:

Background Allocation (BA) – The amount of pollutant that occurs naturally in the watershed
Waste Load Allocation (WLA) – The fraction of the total pollutant load apportioned to point sources, including storm water discharges regulated under the National Pollutant Discharge Elimination System (NPDES)
Load Allocation (LA) – The fraction of the total pollutant load apportioned to non-point sources
Margin of Safety (MOS) – A percentage of the TMDL set aside to account for the uncertainty associated with natural process in aquatic systems, model assumptions, and data limitations.
Thus, the Total Maximum Daily Load can be described as follows:


Point sources of bacteria, for example, include municipal wastewater treatment plants (WWTPs), municipal no-discharge wastewater treatment plants, municipal separate storm sewer discharge, and concentrated animal feeding operations (CAFOs). Non-point sources include pollutants that may arise from many sources, e.g., septic systems or nutrients or manure from fields, and are typically separated into urban and rural categories.

TMDLs can be established for large basins or for smaller watersheds. And, they can be set for one or more conditions, including bacterial pathogens, temperature, dissolved oxygen, chlorophyll a, turbidity, pesticides or nutrients such as nitrogen or phosphorous.

The Illinois River Watershed in Arkansas and Oklahoma is an example that focuses on nutrients ( Scientists in Region 6 of the U.S. EPA are developing a watershed model for the Illinois River watershed in Oklahoma and Arkansas to address nutrient water quality impairments. The purpose of this project is to develop a scientifically robust watershed model to determine the reductions in phosphorus loads that are needed to meet water quality standards in both States. This watershed model would identify nutrient reductions needed to ensure that water quality standards for phosphorus are protected in both States, and as such could serve as the basis for one or more TMDLs for the Illinois River Watershed.

Oklahoma has completed TMDLs on a number of basins or watersheds ( For the last three years, Oklahoma has been in the top 10 of states in reducing pollution of its streams and rivers and in 2011 was ranked number two in that category by the USEPA.

Figure 1. Number of TMDLs completed per fiscal year (EPA fiscal year starts Oct. 1 ends Sep. 30)

The Canadian River Basin is another example. It exceeded the limits for primary or secondary body contact for recreation water quality standards because three pollutants (fecal coliform, E. coli, Enterococcus spp.) exceeded Oklahoma’s current pathogen criteria based on USEPA guidelines (See Implementation Guidance for Ambient Water Quality Criteria for Bacteria, May2002 Draft; and Ambient Water Quality Criteria for Bacteria-1986, January 1986). The details of the calculation of TMDL for the Canadian River Basin can be found in the final report. (

Using data from 2008, which was a representative reporting year, the major causes of impairment for the state as a whole were pathogens, total dissolved solids, turbidity and dissolved oxygen. (


Oklahoma has a well-established TMDL process, the process has been used in several river basins and watersheds, and the state has a chronological plan to continue to address the 303d-listed water bodies. Implementing the TMDL procedures has identified a number of opportunities for future consideration with respect to future analyses of relevant data and information.

Several agencies are involved with collecting water quality data and the associated policies. The Oklahoma Department of Environmental Quality is responsible for the TMDL process and the Oklahoma Water Resources Board is responsible for developing the State’s water quality standards and also for the large-scale Beneficial Use Monitoring Program (BUMP). The Oklahoma Conservation Commission conducts an extensive water quality-monitoring program, primarily in support of the non-point source program. The Oklahoma Corporation Commission is also involved in monitoring water quality, particularly near oil and gas fields. In completing the Fort Cobb watershed TMDL, for example, data on water quality were used from sampling done by the U.S. Geological Survey, U.S. Bureau of Reclamation, U.S. Fish and Wildlife Service, Oklahoma Water Resources Board and Oklahoma Conservation Commission. Although each of these monitoring programs fits the needs of the specific agency, there may be opportunities to increase coordination among the data collection processes.

Models and Tools

Various mathematical models are calibrated for each site (watershed) and used to predict the components of the TMDL. For example, the SWAT (Soil and Water Assessment Tool) model is used to simulate nutrient loads into a water body. The EFDC (Environmental Fluid Dynamic Code) or the Water Quality Analysis Simulation Program (WASP) models are used to predict water quality in the water body. As more data are collected and models are tested, current models may be improved and new models will be developed and available as potential tools to use in Oklahoma.

Many models used in the TMDL process are focused on prescribed sets of processes, such as loadings from non-point sources. However, watersheds have many components including many land-uses and changing weather/climate. Future models will integrate these components and use a large array of input variables to continue to improve the accuracy and precision of the model results both in the water body and the watershed.

Data reconciliation

Long-term trends in monitoring of water quality are very important in describing the temporal dynamics of the conditions of water bodies. Among the key issues is how to address model validation when hourly or daily flow data are not available. Similarly, measuring conditions in the watershed is important, for example in assessing the impacts of the implementation of best management practices. In many cases, the density and frequency of data collections are not sufficient to support confident conclusions from the analyses and model predictions. In addition, because data are collected at various times before the data are used in models, it is important to be sure that the loadings are properly aligned with the model results.

The results of the TMDL process are recommendations on the necessary reductions in pollutant loads and the allocation of these loads among different sources. And yet, the important step in many ways is the plan for actions to reduce the offending pollutants. Future TMDL processes in Oklahoma might incorporate both economic models to assess the impacts of various responses to the TMDLs along with modeling various restoration scenarios.


Oklahoma’s Water Quality Standards (OWQS) are rules (Oklahoma Administrative Code, Title 785, Chapter 45) that provide the baseline against which the quality of waters of the state are measured. These standards, which are the statutory responsibility of the Oklahoma Water Resources Board (, include two primary components:

The beneficial uses ascribed to a water body, such as agriculture, hydroelectric power, fish and wildlife propagation, drinking water, or recreation.
The numerical or narrative criteria that are assigned to each beneficial use.
Narrative criteria are descriptions of desired conditions. Numerical criteria are usually maximum or minimum concentrations of factors such as nutrients, suspended solids, siltation, Trophic State Index (chlorophyll a), dissolved oxygen, pesticides or conditions of the water column. The criteria of one factor may be contingent on other characteristics of the water body, such as pH, temperature or season. And, the same criteria in a water body may be different for different beneficial uses. In establishing TMDLs, the most stringent criterion is usually applicable.

Decisions about whether a water body is impaired are based on a set of rules, described by the Use Support Assessment Protocols (USAP) ( that define how beneficial uses are assessed and whether the beneficial use for a particular water body is fully supported, partially supported or not supported. Whether a water body is impaired is based on the Integrated Water Quality Assessment Report (Integrated Report) that includes the Assessment Methodology describing the data and the decision tree to be used in deciding the conditions under which a water body may be considered impaired. There are five possible attainment conditions:

Category 1 – all beneficial uses assessed and attained

Category 2 – some beneficial uses assessed, no impaired uses

Category 3 – not enough information to assess beneficial uses

Category 4 – one or more uses impaired, but no TMDL required

Category 5 – one or more uses impaired, TMDL required

Category 5 is the State’s 303(d) List of Impaired Waters.

Beneficial use designations include the following:

Drinking water
– Treated/untreated
Water-based recreation
– Noncontact/short-term/long-term
Aquatic life
– Warm water species/habitat
– Cold water species/habitat
Agriculture water supply
Industrial water supply
Oklahoma’s 2008 “303d” listed water bodies, along with the dates for TMDL analyses and the priority scale for future TMDL analyses can be found at In 2010, four streams were removed from this list (

In Oklahoma, the Oklahoma Department of Environmental Quality (ODEQ) sets the TMDLs ( ODEQ is required to submit all TMDLs to U.S. Environmental Protection Agency for review and approval. Once the USEPA approves a TMDL, the water body may be moved to Category 4a of Oklahoma’s Integrated Water Quality Monitoring and Assessment Report (, where it remains until compliance with water quality standards is achieved.

Several state agencies have some responsibility to address point and non-point pollutant source reduction goals established by TMDLs. Nonpoint source pollution is managed by the Oklahoma Conservation Commission (, primarily though incentive-based programs that support the installation of best management practices. The Oklahoma Water Resources Board ( provides support, public education and outreach. The Agricultural Environmental Management Services (AEMS) of the Oklahoma Department of Agriculture, Food and Forestry (ODAFF) ( oversees environmental policies and programs aimed at pollutants associated with agricultural animals and their waste through regulations established by the Oklahoma Concentrated Animal Feeding Operation Act.

As authorized by Section 402 of the CWA, the Oklahoma Department of Environmental Quality manages the NPDES Program in Oklahoma, except for certain jurisdictional areas related to agriculture and the oil and gas industry retained by State Department of Agriculture and Oklahoma Corporation Commission, for which the USEPA has retained permitting authority. The NPDES Program in Oklahoma is implemented via agreement between ODEQ and U.S. Environmental Protection Agency ( Implementation of point source Waste Load Allocation (WLA) for the TMDLs is done through permits issued under the OPDES program (

The Oklahoma Department of Environmental Quality (ODEQ) targets available funding and technical assistance to support pollution controls and management measures designed to achieve the reductions required by TMDLs. ODEQ’s Continuing Planning Process (CPP) ( 2002_cpp_final.pdf), required by the CWA §303(e)(3) and 40 CFR 130.5, summarizes Oklahoma’s commitments and programs aimed at restoring and protecting water quality throughout the State.


The true value and benefit of the TMDL process lies in the effectiveness of the implementation plans to achieve attainment goals for water quality. These plans are generated by the states to secure federal funding under the Clean Water Act and TMDL program. A major drawback is the lack of sufficient guidance to prepare comprehensive watershed implementation plans. As a result of this lack of guidance the states are given flexibility in the development of these plans. This results in significant variability in the plans among the different states. The USEPA continues to update its guidance and the recent development of “Watershed Central” and other efforts by EPA should improve the effectiveness of the TMDL process (

Ground Water Monitoring: Its Importance for Oklahoma and the Oklahoma Water Survey Web Portal


Water is continually on the move on earth and within the earth’s atmosphere. It connects everything and all life depends on it. It exists as a solid (ice), liquid, and gas (water vapor). It is present in the air, on land, beneath the land surface, and in the seas. It not only varies spatially in its quality and quantity, but also temporally; some deep ground waters are thousands of years old.

In describing the hydrologic cycle or the movement of water on earth, one can choose to start anywhere in the cycle. As water vapor is transported through the atmosphere by winds and air currents, it cools, condenses and falls to earth as precipitation. This can be as rain, ice, sleet, or snow. This precipitation may then be intercepted and taken up by plants, infiltrate into soils, or flow over the surface into streams, rivers, lakes, and oceans. Water on the surface returns into the atmosphere via evaporation. It can also return to the atmosphere via evapotranspiration through plants. Water infiltrating soils may continue downward movement to saturated zones in the subsurface, where it becomes ground water.


The top of ground water is called the water table and its location relative to the ground surface can change depending on geology, precipitation events, and well pumping. Ground water can be connected directly to surface water such as lakes, wetlands, streams and rivers. Water can move from ground water to surface water (e.g. gaining streams) or from surface water into ground water (e.g. losing streams). This can be reversed at the same location of the ground water – surface water interface (GSI) depending on precipitation and other water inputs (e.g. release of water from reservoirs) or withdrawls (e.g. well pumping). Therefore, to focus solely on surface water behavior for water quantity and quality management can be a fatal flaw in any water resource management effort.

from USGS Circular 1139
Some interesting facts about water

Only 3% of the earth’s water is fresh water, that is of drinking water quality
97% of the water on earth is salt water
69% of the fresh water is trapped in glaciers leaving only 1% of the total fresh water as available
30% of all fresh water is ground water and the main source of drinking water for people living in rural areas.
Ground water is often taken for granted because of “out of sight-out of mind mentality”. Groundwater accounts for approximately 50 percent of the total reported water use in the state of Oklahoma; surface water accounts for the remaining 50 percent (State of Oklahoma, Groundwater Monitoring and Assessment Program, 2012, OWRB White Paper). Understanding the connections between ground water and surface water as part of the hydrologic cycle is crucial to successfully managing our states’ water resources. Increasing demands for sources of water, combined with changing land use, population growth, aging infrastructure, and climate change, poses significant threats to our water resources. Failure to manage our state’ waters in an integrated, sustainable manner will limit economic prosperity and jeopardize both human and aquatic ecosystem health.


Ground water – surface water interactions (GSI) are integral to the management of our ground water and surface water resources. It is at this interface where sharp variations in oxygen levels, microbial processes, and sediment-water chemical reactions occur. This zone is called the hyporheic zone. It is an important source of nutrient uptake via microbial processes, and adsorption-precipitation reactions controlling metals, nutrient and organic compound transport. A proper understanding of the hydrologic system must look at the entire unit of surface water and adjoining ground water and in particular, the hyporheic zone. Use of stream gauges alone cannot give us an accurate picture of surface water quantity and variations or trends in that resource in terms of both quantity and quality. Ground water monitoring wells are also needed and can be used to monitor water quantity and quality over time in our major aquifers. The addition of more real-time monitoring wells to the few that currently exist in Oklahoma will provide a complete picture of our water resource quantity and quality.

from USGS Circular 1139


Ground water monitoring can provide information on short-term and long-term changes in groundwater recharge, aquifer storage, and climate variability impacts. A fully developed and integrated ground water monitoring program can assist with management decisions on regional interstate and regional intrastate effects of ground-water usage, availability, trends, and quality. These wells would also provide valuable information on interactions between ground water and surface water and provide the basis for more accurate ground-water flow and contaminant transport modeling at local and sub-regional scales.

According to recent surveys by the National Ground Water Association, the Ground Water Protection Council and others and summarized in “A National Framework for Ground-Water Monitoring in the United States” (2009), Oklahoma has a statewide ground-water level monitoring program but there are only a few wells that provide continuous monitoring data. As far as a ground water quality network, the surveys indicate that it is inactive in Oklahoma. Sixty-seven aquifers and aquifer systems have been identified by the USGS as principal aquifers in the U.S. (USGS, 2003, Principal Aquifers of the United States, prepared by the USGS for The National Atlas, scale 1:5,000,000). All or parts of eight of those sixty-seven are in Oklahoma, including the High Plains, Rush Springs, Central Oklahoma, Ada-Vamoosa, Ozark Plateau, Blaine, Arbuckle-Simpson, and Edwards-Trinity aquifers. As of April 2012, the OWRB in cooperation with the Oklahoma Mesonet ( has continuous real-time records for five wells. The Oklahoma City USGS Water Science Center has fifteen operating continuous real-time monitoring wells (

Real-time continuous data appears to be completely absent for two of the eight aquifers in the state and three others only have one well.

The need for a state-wide ground-water monitoring network is profound. The lack of one limits our ability to adequately manage our states water resources. Impacts to ground water cannot be assessed in a timely manner without such a network. The 2012 Oklahoma Comprehensive Water Plan called attention to the fact that characterization of ground water quality and projected future available quantities was not possible due to the lack of long-term data and indicated that such data will only become more important with time in light of forecasts that suggest more reliance on ground water to satisfy state water needs. This same trend has been observed in many other parts of the country.

A strategic monitoring well network needs to be established for the state that is capable of real-time monitoring of water levels at a minimum. The network should be established to monitor water resource trends for all eight major bedrock aquifers and to provide real-time data on GSI for most of the eleven major alluvial aquifers. The 2012 Oklahoma Comprehensive Water Plan (OCWP) recommended ground water quality/quantity funding for 2012 at $815,000. In the state budget for 2013, the Oklahoma legislature and the Governor have adopted and funded many of the high priority recommendations in the OCWP including 1.5 million dollars for water monitoring. The OWRB is currently developing a statewide Groundwater Monitoring and Assessment Program. This will allow for the establishment of a basic network as described above and would be a model for other states in the region and the country.

A comprehensive ground water monitoring network is important for the following reasons:

short and long-term changes in storage and recharge
short and long-term impacts from climate variability
regional intrastate and interstate effects from ground water withdrawls
interactions between ground water and surface water
ground water contaminant transport and resultant impacts to ground water and surface water bodies

In addition to continuously monitored wells by OWRB/Mesonet and USGS, other entities in the state have monitoring well data. This includes both water level and water quality data; however there is no central repository for the data or public access. A publically accessible web portal is proposed for the Oklahoma Water Survey. This would provide a central location for water resource information throughout the state for use by the public and water resource managers. With population increase, land use changes and climate variability there is an increasing need for fresh water, and ground water use is increasing. Based on water levels observed in a few wells, storage in some aquifers appears to be decreasing, but additional data collection along with better estimates of use and available supply are needed to determine changes in storage. Increased use of computer systems by municipal, state and federal agencies now make it possible to realistically attempt better coordination of data from multiple sources and platforms so that trends in water supply and water quality can be observed and not just inferred.