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Agricultural alterations - Alterations that deal with human activities to increase agricultural productivity.


Alluvial fan - A fan-shaped deposit where a fast flowing stream flattens, slows, and spreads typically at the exit of a canyon onto a flatter plain.


Anastomosed - Streams that have multiple threads but do not migrate laterally.


Aquifer - A geological formation capable of storing and yielding significant quantities of water. It is usually composed of sand, gravel, or permeable rock which lies upon a layer of clay or other impermeable material. This impermeable layer does not allow the water to penetrate to lower depths. Thus, various aquifers can be present at various depths.


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Basin and Range - The region characterized by numerous mountain ranges separated by lower elevation basins.


Bedload sediment - The material that usually travels in short bursts or rolling over along the channel bed. The bedload moves the largest material.


Biomes - Major ecological community types determined primarily by climatic factors such as tropical forest, grasslands, deserts, etc.


Braided - Stream channels that have multiple threads with many sand bars that migrate frequently.


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Central Arizona Project (CAP) - The main surface water distribution system in Arizona. In this system, 1.5 million acre-feet of water is removed yearly form the Colorado River to accommodate the metropolitan areas of Phoenix and Tucson.


Central Highlands - The region receiving relatively high rainfall; many small streams and lakes are found in this region.


Channel - The natural stream that conveys water; a ditch or channel excavated for the flow of water.


Channel gradient - Slope of the stream.


Channelization – Human alterations to a stream that include making it straighter, wider and deeper compared to what the natural stream used to be.


Colorado Plateau - The region containing flat-topped mesas, cliffs and multi-colored badlands carved by water, forests, and wind-swept deserts.


Consumptive water uses - Water used is not returned back to its source or is returned to its source in a much lower quality.


Corridor – Linear type of patch (see also definition of a patch).


Cross section - Characterized as the two-dimensional shape of the channel perpendicular to the direction of flow.


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Deposition - The act of depositing materials; in geology refers to materials that have been moved by some mechanical, biological, or other physical process.


Dispersal - Movement of an individual or population of individuals to a new area.


Dissolved load sediments - Constituents of material (salts, chemicals) that are chemically dissolved in the runoff. The dissolved load moves the smallest material.


Drought - Extended period of time with significantly below average precipitation that decreases the soil moisture, surface stream flow and ground water level.


Dynamic equilibrium - This occurs when a long term balance between water and sediment may form such that the channel neither aggrades nor degrades. This can occur when climate remains relatively stable and no disturbance occur (fire, stream regulation, etc.).


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Ecosystem - Functional system that includes organisms like plants, animals, (biotic) and their environment (abiotic).


Ecotones (or transitional zones) - This zones have characteristics of all the adjacent ecosystems and tend to be very rich in the number of species present. One of the main characteristics of an ecotone is the active interactions that take place between two or more of the adjacent ecosystems, with the appearance of ecological processes that do not exist in either of the adjacent ecosystems.


Endangered species - A species of animal or plant threatened with extinction.


Entrenchment - Erosional process in a stream causing the stream bed to become much deeper, typically because of some type of disturbance (natural or human induced).


Ephemeral flow - Flow occurs only occasionally after storms, and is typical of semiarid and arid environments. Flow is not connected to the ground water.


Ephemeral streams – Streams have flow only after precipitation events and the streambed is generally well above the water table.


Erosion - The wearing away and removal of materials of the Earth’s crust by natural means; includes weathering, solution, corrosion, and transportation.


Evaporation - The loss of water as vapor from surfaces such as streams, lakes, puddles, ponds, and soil pores. Evaporation can also occur in the atmosphere.


Exotic species - Plants and animals not native to an area.


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Facultative riparian plants - plant species are commonly found in the upland and riparian areas. These plants have the probability of being found in riparian 26-75% of the time.


Fauna - Collective term for animal life.


Flood - A relatively high stream flow that overtops its natural or artificial banks of the stream or river and causes or threatens damage.


Flora - Collective term for plants.


Fluvial processes - Processes by which water flowing through a drainage network acts to erode, transport, and deposit sediment.


Functions - The ecological, hydrological or other phenomena that contribute to self-maintenance.


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Gabions - Wire cages filled with rocks that are often stacked and used to reduce erosion along steep slopes and stream banks.


Geology - The science of building rocks, mountains and valleys—the basic foundations of watersheds.


Groundwater flow - Water that moves through the soil’s saturated zone (beneath the water table).


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Habitat - The place where an organism lives and is comprised of both biotic and abiotic factors.


Hydric soils - Anoxic saturated soils whose chemistry differs markedly from aerobic riparian or upland soils. They are sufficiently wet in the upper part of their profile to develop anaerobic (no oxygen) conditions during the growing season.


Hydrograph - Describes stream flow discharges through time.


Hydrologic cycle - The movement of water between the atmosphere, organisms, the earth’s surface and below the earth surface.


Hydrologic and geomorphic alterations - Alterations that deal with changes in the hydrology and sediment transport of streams that consequently impact the health of riparian areas.


Hydromodification - The alteration of the hydrologic characteristics of surface waters.


Hydroriparian areas - Areas that are associated with perennial or intermittent water.


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Infiltration - The soil's capacity to allow water to penetrate the surface.


Infiltration rate - A measure of the soil’s capacity to allow water to penetrate the surface.


Intermittent flow - Flow that occurs for at least one month per year, generally in response to seasonally generated runoff. Flow can receive high inputs of ground water or lose significant amounts of water to ground water but is connected to the ground water.


Intermittent streams - Streams that are directly connected to the groundwater but flow in stream channels is typically for only a couple of weeks or months each year.


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Lentic riparian areas - Areas along the banks of water bodies with stationary water (lakes, ponds, wetlands).


Levees - Large linear embankments parallel to rivers and streams of all sizes to protect from flooding events.


Lotic riparian areas - Areas along the banks of moving water (streams and rivers).


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Matrix - The dominant land cover on the land surface, for example a riparian area can occur within the matrix of the Sonoran desert.


Meander - The sinuous lateral path of a stream.


Meander length - The distance from the beginning to the end of a meander.


Migration - Seasonal movement of an individual or population of individuals between habitats.


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Nonpoint source pollutants - Pollution originating from runoff from diffuse areas (land surface or atmosphere) having no well-defined source.


Nonriparian plants - Plants that are not commonly found in riparian areas. The probability of finding them in riparian areas is 0-25% of the time.


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Obligate riparian species - An organism that requires riparian habitat to complete some portion of its life cycle. Obligate riparian plants have the probability of being found in riparian areas 91-100% of the time.


Obligate wetland plants - plant species are found almost exclusively in wetlands. Synonymous to phreatophytes.


Overland flow - Water from precipitation or snowmelt that does not infiltrate into the soil and as a result moves over the surface of the landscape.


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Patch – A relatively homogenous area that differs from its surroundings, for example a cottonwood willow patch type may occur in a riparian area. Patches are typically non-linear and less abundant than the matrix (also see definition of matrix).


Perennial flow - Flow that occurs continuously with substantial inputs from groundwater.


Perennial streams - Streams that have flow in the stream channel throughout the year and substantial inputs from groundwater.


Phreatophytes - Water-loving plants; refers to plants whose roots generally extend downward to the water table. Synonymous to obligate.


Precipitation - Water that condenses into droplets or ice crystals and falls to the ground in various forms like: rain, snow, hail, freezing rain, and fog drip.


Preferential riparian plants - Plants should be found in riparian 76-90% of the time.


Prior Appropriation Doctrine - The first user of the water has the first right to the water. Ownership of the water is transferred with the deed or the title to the property and remains with it as long as the water continues to be put to beneficial use once every five years.


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Regions - Large scale landscape features that are determined by the underlying geology. Arizona can be divided in three main regions that are: Basin and Range, Central Highlands and Colorado Plateau.


Riparian Doctrine - Landowners adjacent to a water body have the right to use some of that water, as long as they do not interfere with the navigation of the waterway or do not reduce the quantity or quality of the water for downstream users.


Riparian areas - These areas have no universally accepted definition. All definitions have certain common points: 1) these areas are adjacent to a body of water and dependent on perennial and intermittent water, 2) these areas have no clearly defined boundaries, 3) they are transitional zones between aquatic and terrestrial environments and 4) these areas are linear in nature.


Riparian soils - Soils that tend to have a wide range of textures and many different stratified sediment layers. This is due to the frequent flooding events that result in the soils being wet for significant parts of the year.


Riparian vegetation - Vegetation that is distinct to their upland counterparts because of their density and species. Riparian vegetation receives significantly more amount and sources of water and are more adapted to disturbances, particularly flooding, compared to uplands vegetation.


Runoff - The water that runs off the soil's surface when precipitation exceeds the capacity of the ground to absorb it.


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Scarp - Typically the outside bend of the channel that erodes.


Sediment - Geologic deposits from water; mineral particles derived from soil, alluvial or rock materials moved by water; sediment also refers to material suspended in water or recently deposited from suspension.


Sediment load - Sediment transported as suspended or bed load in streams.


Sediment yield - The total amount of sediment moving downstream from a specific point of the stream. The sediment that is deposited in the stream channel and not moving downstream is not included in the sediment yield.


Sinuosity - Calculated as the distance water flows along the deepest channel path divided by the straight line distance between starting and ending points.


Straight - Channels that have a single thread that is straight.


Stream flow - The water running within a drainage feature such as a stream channel.


Stream flow discharge - The volume of water passing a point for a specific period of time.


Stream order - A classification based on the type and number of tributaries contributing to a particular stream reach. Stream orders provide a way to rank relative sizes of channels in a drainage basin.


Stream pattern - The planform of a channel (planimetric view). The main characteristics used to separate the patterns are the number of threads (single or multiple), sinuosity and stream channel migration in a stream with multiple threads.


Suspended sediment – The material that are in suspension if the drag and lift forces exerted on the particle by the flow exceed the submerged weight of the particle.


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Thalweg - The channel's deepest part.


Threatened species - A species which is likely to become endangered.


Transmission losses (also called abstractions) - The water that infiltrates into the channel bed and banks during stream flow.


Transpiration - The loss of water as vapor from plant pores.


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Upland - Areas significantly far away for a water course or water body; water from the water course or body will not influence the soils or vegetation.


Upland plant species - Species that are rarely found in wetland.


Urbanization – Significant increase of the human population in a specific area such that it will constitute a city.


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Values - Something of worth, desirable or useful to humans.


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Washload - Material that are chemically dissolved in the runoff. The dissolved load moves the smallest material.


Washload sediments - see dissolved load sediments.


Water balance - A common method to summarize the amount of water that is cycling from the atmosphere, across the land surface, into the ground, through plants, into the ocean, and back to the atmosphere through evaporation.


Water-loving vegetation - Plants that use significant amounts of water.


Watershed - Comprises of all the area that drains to a lower elevation such as a channel, stream, river, lake or other water body.


Wetland – Have three main characteristics: 1. Their soils or substrates are saturated or covered by shallow water at some time during the growing season. 2. Their plants in these environments are adopted to grow in water, soil or substrate that is occasionally oxygen-deficient because of water saturation. 3. Their hydric soils are saturated long enough during the growing season to produce oxygen-deficient conditions in the upper part of the soil occupied by plant roots.


Width to depth ratio - The width of the channel divided by the average depth of the channel.


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