Cypress Creek Project



HOME ABOUT Vision Background Partners Glossary MAPS & DATA Maps Reports Photos Monitoring NEWS Join Newsletter Meetings EDUCATIONCONTACT US ForumSITE MAP		Glossary of Terms In this glossary: Decision Support Systems (DSS) Erosion and Sedementation Flooding Karst Non Point Sourcs (NPS) Pollution Point Source Pollution Pollution Watershed Watershed Model Watershed Protection Plan The following list of terms will be frequently used for the Cypress Creek Project. We will continually add to this list during the life of the project. In addition, the US Geological Survey has gathered many water-related terms that might be helpful: http://ga.water.usgs.gov/edu/dictionary.html. Decision Support Systems (DSS) for watershed planning are computerized information system that supports decision-making activities. They are designed to provide information to assist resource managers in solving complex problems, such as those faced by local planners, managers, and stakeholders wishing to allow for economic growth, while preserving water quality and protecting the local environment. Watershed planning DSS make use of a wide variety of data, applying analytical and statistical modeling capabilities and multi-criteria evaluation to analyze alternative development strategies and to suggest methods to mitigate runoff and nonpoint source pollutant increases from proposed developments. The primary focus of DSS design is oriented toward decision makers, so stakeholder input is critical throughout its development. The end goal of DSS design is to provide a user-friendly interface, typically relying on graphical displays that can present decision-makers with targeted information, given particular scenarios of land development or other issues of concern to the stakeholder community. An ideal DSS will be transparent, easy to use, flexible enough to incorporate different styles of problem solving, and adaptable to new capabilities as required. Back to Top Erosion and Sedementation are the movement of water, wind, and ice across the land’s surface wears away the rock and soil, carrying the particles from their source. This process is known as erosion. Erosion of land surfaces and stream banks produces sediment through a three stage process. Particles are detached from their original soil or rock body. Then, the detached particles are transported by flowing water, wind, or other forces. Finally, the transported particles are deposited in a process known as sedimentation. Geologic or “natural” erosion is an inevitable process that takes place continually. This slow process, however, is greatly accelerated by human activity. Today, sediment is a major global concern that threatens water supplies, recreation, and wildlife and associated habitat. Sediments can carry with them other pollutants like pathogens, nutrients, and toxics, further exacerbating water quality problems. The rate of soil erosion is affected by several natural and anthropogenic factors including: Rainfall: Intensity and duration of rainfall both affect erosion rates. High energy rainfall over short time periods as well as low energy rainfalls over longer periods can produce significant erosion. *Soil:* Soil erodibility includes soil texture and percent organic matter. In general, soils with faster infiltration rates, higher levels of organic matter and improved soil structure have a greater resistance to erosion. Sand, sandy loam, and loam textured soils are often less erodible than silt, very fine sand, and certain clay textured soils. *Slope:* Slope angle and length can have a large effect on erosion. Steeper slopes are more susceptible to erosion. Erosion also increases as the slope length increases due to the greater accumulation of runoff. *Vegetation:* Plant cover can prevent erosion by stabilizing the soil and minimizing soil damage from raindrop impact. Different types of vegetation can provide varying degrees of protection. *Conservation practices:* Land management practices implemented to control erosion like vegetative riparian buffers and silt fences can significantly reduce soil loss. Human activities including urbanization, agriculture, forestry, and mining to name a few can remove a landscape’s natural resistance to erosion. For example, sediment concentrations in urban runoff occur primarily from soil erosion and runoff from construction sites. Areas under construction have been shown in some studies to produce 10 to 100 times more sediment than is found in otherwise comparable rural or natural areas. Agricultural activities consist of removing an area’s natural vegetation and introducing a selection of domesticated and specialized crops. The act of removing the native vegetation to make the soil receptive to planted crops increases the soils vulnerability to erosion. The soil’s top layer is most vulnerable to erosion and this is also often the soil’s most fertile layer, being richest in nutrients. Loss of the topsoil often requires the use of more fertilizers to compensate for reduced natural fertility. Increased sediment in runoff may cause significant biological, chemical, and physical changes in receiving waters. Changes can include loss of water clarity, decreased light penetration through the water column, clogging of gills and filters of aquatic organisms, and aquatic habitat degradation particularly for benthic communities. In addition, waterways filled with deposited sediments have a reduced capacity to transport floodwaters in times of high flow. This is a frequent problem in urban areas where construction releases large amounts of sediment, which are then deposited in storm drains or natural channels. Once sediments are deposited, removal and maintenance can be costly. In Texas, water quality degradation from sediments is an unfortunate reality. Fortunately, sedimentation can be controlled with land management strategies designed to keep soils and associated pollutants from ever entering the waterways. Many responsible companies, farmers, cities, and community members have effectively reduced sedimentation in their area through land management. (Dunne, T. and L. B. Leopold (1978). Water in Environmental Planning. New York, W.H. Freeman and Company.; Hillel, D. (2004). Introduction to Environmental Soil Physics. New York, Elsevier Academic Press.; Morgan, R. P. C. (1995). Soil Erosion and Conservation. Essex, Longman Limited.) Back to Top Flooding liklihood increases with urbanization for several reasons including, but not limited to, increased impervious cover and removal of first order streams. In more natural, vegetated settings, rainfall infiltrates into the soil and percolates into the groundwater system. Urban areas have more impervious cover due to the many roads, parking lots, buildings, etc. In these areas the water is unable to infiltrate. Instead, it travels over the land directly into the stream. The result is more water entering the channels during any one particular rain event. Due to the larger flows, the water speed increases in the channel. The erosive power of the fast-moving water causes an increased sediment yield. Urbanization usually also decreases the drainage density, or number of channels, to carry the water in an area. During development, first-order channels are often eliminated by grading or put in a pipe. The result is the elimination of channels that played a role in keeping both sediment and run-off distributed and divided among many small channels, each of which played its part in delaying movement of flood peaks, providing channel storage and slowing the average speed at which water was delivered to the larger stream channels. (Dunne, T. and L. B. Leopold (1978). Water in Environmental Planning. New York, W.H. Freeman and Company.) Back to Top Karst areas contain soluble rocks, such as limestone, whose structure are dominated by interconnected conduits created by dissolution. Unique characteristics of karst areas include (1) general lack of permanent surface streams; (2) the existence of swallow holes into which surface streams sink; (3) the presence of underground channels (conduits or drains) in which rapid water flow occurs; (4) the occurrence of large springs (Kacaroglu, 1999). The Cypress Creek watershed is predominately a karstic limestone region. This type of feature is also common globally. Approximately 25% of the land surface of the earth is karst (Hao, 2006). Karst areas are highly susceptible to groundwater contamination for several reasons. The dissolved rocks form conduits and channels for underground flow and increase the ability of water to enter into these conduits from the surface. Secondly, the protective rock and soil deposits normally found in non-karst systems are minimal, making the system more vulnerable. Particularly in urbanizing areas, construction can destroy the few covering layers of karst rocks and increase the risk of pollution. Not only is pollution entry into the system a concern, high velocities of groundwater flow through the conduits can also be problematic. Fast pollution transport rates can create detrimental consequences without sufficient time to identify the causes and prevent the effects (Kacaroglu, 1999). (Kacaroglu, F. 1999. Review of groundwater pollution and protection in karst areas. Water, Air, and Soil Pollution 113:337-356. Hao, Y., T.-C. J. Yeh, and C. Hu. 2006. Karst groundwater management by defining protection zones based on regional geological structures and groundwater flow fields. Environmental Geology 50: 415-422.) Back to Top Non Point Source (NPS) Pollution Non-point source pollution is caused by wind, rainfall, and snowmelt carrying pollutants to surface and ground water systems. As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters, and even our underground sources of drinking water. Atmospheric deposition and hydromodification are also sources of nonpoint source pollution. Because moving water is the most common driving force of non-point source pollutant movement into the waterways, the amount of pollution from non-point sources varies both spatially and temporally. In an urbanizing system such as the Cypress Creek watershed, non-point source pollution threats arise from increased intensity of land use, construction, alteration of natural drainage densities, and soil compaction to name a few. Fortunately, non-point source pollution can be minimized through careful planning to prevent negative impacts. Non-point source pollution does not lend itself directly to the traditional discharge control methods of sampling directly from a pipe to ensure permitted pollution standards are met since the sources are diffuse across a landscape. Instead, non-point source pollution can be assessed to define solutions from a diverse array of land management, educational, and political possibilities (EPA, 1987). Analyses can include, but is not limited to, a physical understanding of the processes driving pollution transport, identification of pollutant sources, social studies of the societal drivers, and economic analyses. (Environmental Protection Agency (1987). Guide to Nonpoint Source Pollution Control. Criteria and Standards Division. Washington, D.C.: 121.) Back to Top Point source pollution comes from a single, identifiable source of pollution such as a discharge from a municipal or industrial wastewater treatment plant. Point sources are regulated under the Clean Water Act and Texas law and are subject to permit requirements that focus on water quality protection. These permits specify effluent limits, monitoring requirements, and enforcement mechanisms (TNRCC, 1999). (Texas Natural Resource Conservation Commission. 1999. Texas nonpoint source pollution assessment report and management program. Austin, TX: SFR-69/69.) Back to Top Pollution is defined as an “undesirable state of the natural environment being contaminated with harmful substances as a consequence of human activities.” Water pollution is “the loss of any of the actual or potential beneficial uses of water caused by any change in its composition due to human activity.” Back to Top Watersheds are nature’s boundaries consisting of all the land that water flows across, under, and through on its way to a particular body of water. Everybody lives in a watershed. Every rain drop of water flows downhill and ends up in a body of water such as a creek, river, lake or ocean. The boundary drawn by the highest point of land surrounding the water body that the raindrop ends up in is the watershed boundary. A watershed is an area of land that contributes water, nutrients, pollutants, and sediments to a common point, the watershed outlet. Watersheds can be large or small. When it rains, water moves downhill across the surface or under ground. Moving farther downhill with the force of gravity, the water converges into a progressively larger system (TCEQ and Texas State University – Watershed Science and Sustainability Lab). The Cypress Creek watershed, located around Wimberley in Hays County has a total area of about 38 square miles (98 square kilometers). Downstream of Wimberley, Cypress Creek joins the approximately 500 square mile (1295 square kilometer) Blanco River watershed (EARDC). Watersheds are impacted by much more than the landscape characteristics that defines them. Human activities and the political and institutional environments within a watershed can also have significant impacts. The Cypress Creek watershed is a rapidly urbanizing ecosystem under increasing demands from a variety of sources. The population of Hays County is expected to grow from 97,589 in 2000 to 509,876 in 2040 (Texas State Data Center). While this projection is for the entire county, much of this growth will occur within the Cypress Creek watershed and adjacent aquifer recharge and contributing zones. Back to Top Watershed Models are computerized representations of a physical watershed. They are primarily used to look at the impacts of land use/ land cover changes or climate variables on specific model outputs, such as stream flow and water quality parameters. They have a much more specific purpose than a DSS. Back to Top Watershed Protection Plan (WPP) is a holistic document that approaches water quality and watershed issues through a collaborative approach by recommending management strategies that address more than one watershed and community concern. It includes an in depth overview of the watershed, defines what the watershed is and what its characteristics are and provides some of the history behind the water quality, watershed health, and community issues that are currently and will be faced in the future. Concerns voiced by stakeholders about the watershed are discussed in detail; management strategies are recommended, an estimate of costs and technical assistance are provided, timelines for implementing these strategies and an ancillary program to address each priority concern are all included in the WPP. Back to Top
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Human activities including urbanization, agriculture, forestry, and mining to name a few can remove a landscape’s natural resistance to erosion. For example, sediment concentrations in urban runoff occur primarily from soil erosion and runoff from construction sites. Areas under construction have been shown in some studies to produce 10 to 100 times more sediment than is found in otherwise comparable rural or natural areas. Agricultural activities consist of removing an area’s natural vegetation and introducing a selection of domesticated and specialized crops. The act of removing the native vegetation to make the soil receptive to planted crops increases the soils vulnerability to erosion. The soil’s top layer is most vulnerable to erosion and this is also often the soil’s most fertile layer, being richest in nutrients. Loss of the topsoil often requires the use of more fertilizers to compensate for reduced natural fertility.
Increased sediment in runoff may cause significant biological, chemical, and physical changes in receiving waters. Changes can include loss of water clarity, decreased light penetration through the water column, clogging of gills and filters of aquatic organisms, and aquatic habitat degradation particularly for benthic communities. In addition, waterways filled with deposited sediments have a reduced capacity to transport floodwaters in times of high flow. This is a frequent problem in urban areas where construction releases large amounts of sediment, which are then deposited in storm drains or natural channels. Once sediments are deposited, removal and maintenance can be costly. In Texas, water quality degradation from sediments is an unfortunate reality. Fortunately, sedimentation can be controlled with land management strategies designed to keep soils and associated pollutants from ever entering the waterways. Many responsible companies, farmers, cities, and community members have effectively reduced sedimentation in their area through land management.
(Dunne, T. and L. B. Leopold (1978). Water in Environmental Planning. New York, W.H. Freeman and Company.; Hillel, D. (2004). Introduction to Environmental Soil Physics. New York, Elsevier Academic Press.; Morgan, R. P. C. (1995). Soil Erosion and Conservation. Essex, Longman Limited.)

Flooding liklihood increases with urbanization for several reasons including, but not limited to, increased impervious cover and removal of first order streams. In more natural, vegetated settings, rainfall infiltrates into the soil and percolates into the groundwater system. Urban areas have more impervious cover due to the many roads, parking lots, buildings, etc. In these areas the water is unable to infiltrate. Instead, it travels over the land directly into the stream. The result is more water entering the channels during any one particular rain event. Due to the larger flows, the water speed increases in the channel. The erosive power of the fast-moving water causes an increased sediment yield.
Urbanization usually also decreases the drainage density, or number of channels, to carry the water in an area. During development, first-order channels are often eliminated by grading or put in a pipe. The result is the elimination of channels that played a role in keeping both sediment and run-off distributed and divided among many small channels, each of which played its part in delaying movement of flood peaks, providing channel storage and slowing the average speed at which water was delivered to the larger stream channels.
(Dunne, T. and L. B. Leopold (1978). Water in Environmental Planning. New York, W.H. Freeman and Company.)

Karst areas contain soluble rocks, such as limestone, whose structure are dominated by interconnected conduits created by dissolution. Unique characteristics of karst areas include (1) general lack of permanent surface streams; (2) the existence of swallow holes into which surface streams sink; (3) the presence of underground channels (conduits or drains) in which rapid water flow occurs; (4) the occurrence of large springs (Kacaroglu, 1999). The Cypress Creek watershed is predominately a karstic limestone region. This type of feature is also common globally. Approximately 25% of the land surface of the earth is karst (Hao, 2006).
Karst areas are highly susceptible to groundwater contamination for several reasons. The dissolved rocks form conduits and channels for underground flow and increase the ability of water to enter into these conduits from the surface. Secondly, the protective rock and soil deposits normally found in non-karst systems are minimal, making the system more vulnerable. Particularly in urbanizing areas, construction can destroy the few covering layers of karst rocks and increase the risk of pollution. Not only is pollution entry into the system a concern, high velocities of groundwater flow through the conduits can also be problematic. Fast pollution transport rates can create detrimental consequences without sufficient time to identify the causes and prevent the effects (Kacaroglu, 1999).
(Kacaroglu, F. 1999. Review of groundwater pollution and protection in karst areas. Water, Air, and Soil Pollution 113:337-356.
Hao, Y., T.-C. J. Yeh, and C. Hu. 2006. Karst groundwater management by defining protection zones based on regional geological structures and groundwater flow fields. Environmental Geology 50: 415-422.)

Non Point Source (NPS) Pollution Non-point source pollution is caused by wind, rainfall, and snowmelt carrying pollutants to surface and ground water systems. As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters, and even our underground sources of drinking water. Atmospheric deposition and hydromodification are also sources of nonpoint source pollution. Because moving water is the most common driving force of non-point source pollutant movement into the waterways, the amount of pollution from non-point sources varies both spatially and temporally. In an urbanizing system such as the Cypress Creek watershed, non-point source pollution threats arise from increased intensity of land use, construction, alteration of natural drainage densities, and soil compaction to name a few. Fortunately, non-point source pollution can be minimized through careful planning to prevent negative impacts.
Non-point source pollution does not lend itself directly to the traditional discharge control methods of sampling directly from a pipe to ensure permitted pollution standards are met since the sources are diffuse across a landscape. Instead, non-point source pollution can be assessed to define solutions from a diverse array of land management, educational, and political possibilities (EPA, 1987). Analyses can include, but is not limited to, a physical understanding of the processes driving pollution transport, identification of pollutant sources, social studies of the societal drivers, and economic analyses.
(Environmental Protection Agency (1987). Guide to Nonpoint Source Pollution Control. Criteria and Standards Division. Washington, D.C.: 121.)

Point source pollution comes from a single, identifiable source of pollution such as a discharge from a municipal or industrial wastewater treatment plant. Point sources are regulated under the Clean Water Act and Texas law and are subject to permit requirements that focus on water quality protection. These permits specify effluent limits, monitoring requirements, and enforcement mechanisms (TNRCC, 1999).
(Texas Natural Resource Conservation Commission. 1999. Texas nonpoint source pollution assessment report and management program. Austin, TX: SFR-69/69.)

Pollution is defined as an “undesirable state of the natural environment being contaminated with harmful substances as a consequence of human activities.” Water pollution is “the loss of any of the actual or potential beneficial uses of water caused by any change in its composition due to human activity.”

Watersheds are nature’s boundaries consisting of all the land that water flows across, under, and through on its way to a particular body of water. Everybody lives in a watershed.
Every rain drop of water flows downhill and ends up in a body of water such as a creek, river, lake or ocean. The boundary drawn by the highest point of land surrounding the water body that the raindrop ends up in is the watershed boundary.
A watershed is an area of land that contributes water, nutrients, pollutants, and sediments to a common point, the watershed outlet. Watersheds can be large or small. When it rains, water moves downhill across the surface or under ground. Moving farther downhill with the force of gravity, the water converges into a progressively larger system (TCEQ and Texas State University – Watershed Science and Sustainability Lab). The Cypress Creek watershed, located around Wimberley in Hays County has a total area of about 38 square miles (98 square kilometers). Downstream of Wimberley, Cypress Creek joins the approximately 500 square mile (1295 square kilometer) Blanco River watershed (EARDC).
Watersheds are impacted by much more than the landscape characteristics that defines them. Human activities and the political and institutional environments within a watershed can also have significant impacts. The Cypress Creek watershed is a rapidly urbanizing ecosystem under increasing demands from a variety of sources. The population of Hays County is expected to grow from 97,589 in 2000 to 509,876 in 2040 (Texas State Data Center). While this projection is for the entire county, much of this growth will occur within the Cypress Creek watershed and adjacent aquifer recharge and contributing zones.

Watershed Models are computerized representations of a physical watershed. They are primarily used to look at the impacts of land use/ land cover changes or climate variables on specific model outputs, such as stream flow and water quality parameters. They have a much more specific purpose than a DSS.

Watershed Protection Plan (WPP) is a holistic document that approaches water quality and watershed issues through a collaborative approach by recommending management strategies that address more than one watershed and community concern. It includes an in depth overview of the watershed, defines what the watershed is and what its characteristics are and provides some of the history behind the water quality, watershed health, and community issues that are currently and will be faced in the future. Concerns voiced by stakeholders about the watershed are discussed in detail; management strategies are recommended, an estimate of costs and technical assistance are provided, timelines for implementing these strategies and an ancillary program to address each priority concern are all included in the WPP.