Evaluating land use planning strategies for watershed protection

Watershed Management

Evaluating Strategies for Watershed Protection and Management

The world's watersheds are among the most valuable resources that we have on planet earth. Human beings cannot survive without water. Therefore, managing our watersheds is an important responsibility. Many tools are available for the management of our nation's watersheds. This research will explore two of these tools and examine cast studies to illustrate the advantages and disadvantages of their use.

Land Use Planning

Land use planning is one of the most important tools for land use management. One of the main problems faced by urban planners is uncontrolled growth and urban sprawl, both of which have negative affects on the quality of water available (Kauffman, Brant, & Kitchell). The invasion of the suburbs into natural areas means the continued development of low-density populated areas. As the city begins to spread, it has a number of impacts on the local economy. Sprawl has an impact on local agricultural income, forestry, ecological diversity, tourism and other industries that once used the space as a productive portion of the economy (Watershed Protection Techniques, 1997). In addition, it means the need for a new infrastructure to serve the new community. This taxes resources, such as the need for a sewage treatment plant, and the loss of protected watershed resources. Urban sprawl begins the process of paving the landscape and this has a major impact on the ability of the water cycle to replace the water being utilized by the new community. It is predicted that between the years of 1989-2020 stream quality in the Occuquan basin would decline to the point where they could not support the growing population (Watershed Protection Techniques, 1997).

Impervious cover thresholds have been used to protect streams and watersheds in the Christina River Basin in Delaware. This area of the country has been used by New Castle County, Delaware to protect the streams watersheds that provide nearly 75% of the drinking water for its residents. Impervious cover refers to buildings, roads, sidewalks, and other surfaces in the urban setting. These structures prevent the ability of water to filter back into the ground, maintaining The quantity and quality of water available.

The Impervious Cover Threshold method utilizes surface coverage to provide a measurable, scientifically defensible means to protect watersheds (Kauffman, Brant, & Kitchell). This method successfully provided a way to develop sound policy in the Christina River Basin, demonstrating the effectiveness of the method for urban design. Planners can provide for sufficient "green space" and can calculate the impact of building plans via roof area, on the watershed.

The Impervious Cover Threshold method focuses on developing a strategy for determining the capacity of the watershed to sustain the population. This method focuses on the ability of the watershed to sustain a certain population level. Development capacity of analysis is closely related to this technique in that it utilizes a strategy that focuses on determining if the urban area has sufficient land to accommodate the expected population growth. This strategy utilizes an inventory to determine proper growth patterns and levels that can be supported by the land. Watershed availability and capacity is a key component of this inventory (NCSGRE, 2005). .

Capacity analysis is different for every community. However, the general process is the same. Capacity analysis allows officials to determine the level of developability of the land. These categories include vacant and underutilized land, residentially zoned land, land with urban services, land without physical constraints, land available for purchase development, and ladn economically feasible to develop (NCSGRE, 2005). The general process for determining land capacity involves determining the area of land available that falls into each category and then creating an inventory by area and determining the amount and direction of development that needs to take place according to the area's particular land profile/

Both the Impervious Cover Threshold method and the capacity analysis methods utilize square footage (or acreage) available. The advantage to these methods is that they provide an easily measurable and quantifiable method for determining the effects of urbanization on the land. However, they both have a key drawback in that they do not consider the actual capacity of the available watershed. Including this information would make them more responsive to the actual ability of the watershed to maintain the current and future populations.

Conclusion

The two watershed management strategies utilized in this research work best for planned communities, as these factors can be included in the initial design of the sites and buildings. Once, the buildings are in place, it is difficult to improve watershed management practices after the project is complete. Neither of these techniques can correct mistakes of the past. They focus on the planning stage of the project. They minimize future damage, but can do little to change current infiltration and runoff problems. Parking lot redesign was found to have a significant impact on the treatment of the watershed, but this improvement must be taken into consideration with what would have happened if Better Site Design were used to guide the project in the planning stages.

Of the two methods examined, Better Site Design allows planners to look at a small area and focus on the details of a particular site. Land Use Planning methods look at a larger area and take a macro approach to the problem. Both of these methods utilize impervious cover as their quantitative method. There is one weakness that plagues both of these techniques. It is easier to control public land as opposed to that which is privately owned. Private land owners have considerable freedom to do what they want in terms of impervious cover, as opposed to green space, even in areas that are unzoned. Both Better Site Design and Land Use Techniques suitable in for future planning projects and overall watershed protection.