Oct. 10 Riparian Zones: A riparian zone is an area that is influenced by an adjacent stream or river that processes large fluxes of energy and material. There are two major types of riparian zones: 1. Bottomland hardwood forests 2. Western riparian zones These zones can be low or high order. Low order streams feed into high order streams. Riparians are nutrient sinks in low order areas, the nutrients are deposited into the sediment layer. Riparians are nutrient transformers in high order areas because of all of the aerobic and anaerobic activity. Odum called riparian zones the interface between mans most viable resource, water, and his living space, the land. This shows that riparian zones are of great historical importance. Watersheds: Riparian zones have a high water table because of their proximity to a river or stream. The plants in this zone have their roots into the saturated zone. Riparian zones are ecotones between aquatic and upland systems, meaning that there is a continuous exchange of energy, species, and nutrients. In the east riparian zones can be 10 km wide, while in the west they are usually only a couple of meters wide. There are 36 million ha of riparian zones left in the US. The national loss rate is 2.7% per year. (This is from 1940-1980, 2.8 million have been lost in the past 40 years.) In bottomlands before European settlement there were 21 million ha, today there are 4.9. The existing bottomlands are found from Virginia to Texas. Most of this land is fragmented into 100 ha plots or smaller which makes a poor habitat for animals. In the west, low order steams have suffered a lot of damage from grazing. High order streams have been dammed up. Now the withdrawal of water into these systems is greater than the input on a yearly basis. Southwest Southwest Northwest Northwest Southeast Southeast low order high order low order high order low order high order climate arid, arid, semi-arid, semi-arid, mesic, mesic, ET>>P ET>>P ET>P ET>P ET

From the delta to the Gila river: Hydroriparian (lots of water) Gila to the San Pedro: Mesoriparian (in between) Headwaters of the San Pedro: Xeroriparian (dry, intermittent) Part of this classification is the size of the watershed and how much of the time it is flooded. In Arkansas it was found that >10,000 m2 was flooded 18-40% of the time, 500-700 m2 was flooded 10-18% of the time, and 300 m2 was flooded 5-7% of the time. A channels slope will effect how often it floods and the extent of the flood. The Santa Anna 20 year flood event carried 50 times the annual flow. The 20 year flood event of an eastern river will carry 1.5 times the annual flow. There are 3 zone divisions (refers to sediment and nutrients): 1. Zone of erosion - low order 2. Zone of transport/storage - mid gradient 3. Zone of deposition - high order, low elevation In the west there has been a lot of change in channel morphology. A flood may cut a new channel. The riparian zone here keeps moving back and forth. In the east there are more meandering channels with sow evolution. One side may fill up while the other is being cut. This eventually cuts a new channel in a lake or swampy area. Dams cause a lot of sediment to drop out, there is not as much change in the channels. Oct. 15 1997 or Sept. 3, 1998 Wetland delineation and definitions: There are 5 major agencies dealing with wetland issues: 1. Army Corps of Engineers - interested in construction on wetlands. 401 and 404 regulate fill activities and construction. 2. EPA - interested in pollution, regulated by Clean Water Act. 3. US Fishery and Wildlife Service - interested in wildlife preservation, this is done by the use of the endangered species and national wetlands inventory. 4. US Dept. of Ag. - interested in soil conservation, regulated by 'swampbuster' and the Food Security Act (farm bill). 5. Dept. of Commerce - Coastal Zone Management Act. General permits allow minor activities for all people, these are normal agriculture, forestry, and fill for temporary roads. This can also be called the honor system. As long as your activities are in the bounds of these set guidelines, you are covered under a general permit. If your activities exceed these bounds you must apply for an individual permit. The Army Corps of Engineers has 36 districts. Tucson is in the South Pacific district, and the office is located in L.A. The EPA has 10 regions, if you live in Tucson paperwork must be done through San Francisco. USFWS has 7 regions, and their office is in Albuquerque. USDA has several offices in every county, and also state offices. This shows how difficult it can be for these departments to coordinate because of different regions. Each also has its own manuals which are defined for different reasons. A routine approach is used in obvious, simple cases. Regulators look for obligate hydrophytes which only survive in saturated soils. A comprehensive approach is for large or controversial sites. Here the hydrophyte list is used and hydrophytes, hydric soils, and the hydrology are all looked at. An example of the complicatedness of dealing with several departments: The 1987 manual defined a wetland as being flooded 12.5% of the year or 5% of the growing season. The 1989 manuals definition was 7 days in succession, which is much easier to judge. The National Food Security Act Manual (NFSAM) put out in 1989 by the USDA defines a wetland as having standing water 15 days a year. The critical depth is defined in the 1987 manual as saturation in the root zone, or down 30 cm. The 1989 manual defines the critical depth as between 15-36 cm. NFSAM's definition is saturation at the surface. Growing season is also defined by each of these. The 1987 manual calls the growing season frost-free days. The 1989 manual says the soil temperature must be greater than biological zero (5C) at 50cm. NFSAM says above biological zero, but this can be estimated by the number of frost free days. The good news is that all 3 cases go back to the hydrophyte list (Reed, 1988) which gets updated periodically. The current list has 6,728 species. These are also broken up into obligate wetlands, facultative wetlands, facultative hydrophytes, facultative upland plants, and obligate upland plants. obligate wetland plants - >99% are found in wetland areas. facultative wetland plants - 67-99% found in wetlands, 1-33% not. facultative hydrophytes - 33-67% found in wetlands, 33-67% not. facultative uplands - 1-33% found in wetlands, 67-99% not. obligate uplands - >99% found upland. These departments also use the same definition for hydric soils, soil that in its undrained condition is saturated long enough to become anaerobic. These departments are using a lot more tools to aid in defining wetlands, such as maps, aerial photos, satellite images, GIS and GPS. These tools make definitions more accurate.