From the initial assessment of development-conservation conflict emerged five areas in the region that exemplify important and representative landscape change conditions. They are also conducive to a more detailed study of various conservation-development issues related to the impacts of urbanization on agriculture, riparian zones, and other areas of conservation priority.

The five areas, as shown in Figure 30, are:

Site A - a conservation corridor south of the Santa Rosa Plateau;

Site B - the intersection of Warm Springs Creek and Interstate I-15;

Site C - the intersection of Scott Road and I-215;

Site D - the intersection of Scott Road and Route 79; and

Site E - a conservation corridor east of the Domenigoni Valley Reservoir that is scheduled for completion in the next three years.

Please note that sites C and D are corners of the new City Center.

For each site, existing conditions are identified. The results of the trend of development in 2030 (which ignores any alternative design concept or guidelines) is shown using photo-simulation. Then, the proposed design concept is shown; it attempts to integrate conservation and development and includes guidelines for development. Finally, and for comparison to the trend, the results of the design proposal in 2030 is shown.

Site A lies south of the Santa Rosa Plateau and is upstream from MCB Camp Pendleton. The high-quality habitat and need for connectivity qualify this site for priority 1 conservation status. Still, it contains existing residential and orchard-agricultural areas and has several existing structures built in the floodplain and some on steep slopes (Figure 31). Further development in the area could significantly increase flood vulnerability on Camp Pendleton.

The trend (Figure 32) shows continued building on steep slopes and in the floodplain, as well as new roads bisecting large patches of natural vegetation. Perpetuating these trends will increase fire risk, exacerbate flood hazards, and increase downstream water pollution.

The strategy for this site includes management of the landscape for fire, protection of riparian zones, and conservation of prime areas of habitat for wildlife (Figure 33).

The proposed design maintains contiguous areas of vegetation, including agricultural areas that can also sustain wildlife (Figure 34). Roads are placed at the edges of natural areas to minimize fragmentation effects on habitat. Construction is not allowed on steep slopes, thus reducing fire hazards and soil erosion. To further reduce impacts of development, structures are placed close together, with on-site retention systems that mitigate water pollution, lessen stormwater runoff, and reduce the potential of downstream flood damage. It is important to note that the same number of houses are added in both the trend and the proposed design.

Site B is located at the crossing of Warm Springs Creek and I-15, just south of the intersection of I-15 and I-215 (Figure 35). Located at the edge of the Temecula-Murrieta border and south of Murrieta town center, this site is under intense development pressure; the current prospect of a regional shopping center to be located near this freeway intersection would greatly impact the site.

The trend of development shows commercial and industrial development scattered along all major roads, with industry and housing built in the Warm Springs Creek riparian corridor (Figure 36). If this continues, the creek will become channelized and development will continue to sprawl—which is the antithesis of the design strategy.

The proposed design strategy for this site aims to maintain a flood control network along riparian corridors, cluster commercial development at major intersections, and encourage infill development wherever possible (Figure 37).

The design maintains the integrity of the stream corridor and riparian habitat (Figure 38). A golf course and recreational zone are located near the creek to buffer the stream against the effects of adjacent residential development and to provide emergency flood storage capacity. New commerce and industry are located near the major intersections and in already developed areas.

Site C, the intersection of Scott Road and I-215, is still largely agricultural, with scattered rural-residential housing (Figure 39). This intersection has great potential to expand as a commercial and residential area in any development scheme. The proposed transit line, which follows Route I-215, will have a major station at this intersection, which marks the northwest corner of the proposed City Center.

If this site were to be developed under current trends, industry and commerce would be scattered along all major roads, and especially near intersections in the case of limited access highways (Figure 40). Single-family housing would fill the area. Development would likely take place in the riparian corridor and streams would become channelized as development pressures increase.

The design strategy is to make this site the civic and institutional core of the new City Center, with commerce, industry, and multi-family housing located in its adjacent linear "arms," and directly accessible from new interior boulevards (Figure 41). Conservation corridors buffer the stream network while enabling adjacent single-family housing. Schools are located at intersections of roads and the new conservation corridors.

In the design proposal based on development with guidelines (Figure 42), the civic core of the new City Center, multi-family housing, institutional, commercial, and light industrial development are located between Scott Road and the proposed new inner boulevard. The boulevard has high-quality bus service linking the transit station with all parts of the linear higher-density area. Access to institutions and employment are less dependent on cars. The inner core of the City Center consists predominantly of agriculture, conservation, and recreational land, creating a close relationship between the densest development and the landscape.

Site D marks the northeast corner of the proposed City Center (Figure 43). Much of the site is owned by the Domenigoni family and has agricultural uses on prime agricultural soils. This site is also important because of its adjacency to Warm Springs Creek, to the future reservoir, and to the reservoir park. Much of the land is of high conservation priority.

Under current trend development, Route 79 will be upgraded (Figure 44). The reservoir will be completed with a park built to the west of it; single-family residential subdivisions will cover much of the prime agricultural soils and priority conservation areas. Commercial strip development will locate along the highway.

The design strategy is meant to conserve the most productive agricultural lands, to use conservation corridors as riparian buffers, and to provide recreational access to the adjacent reservoir reserves. Zoning the area east of Route 79 for very low-density, rural-residential development would encourage private conservation in order to promote both connectivity and low-density, high-quality development (Figure 45).

The proposed design preserves the prime agricultural soils that currently support agricultural activity (Figure 46). High-priority conservation areas are minimally impacted; significant development can be accommodated and farmers can continue to farm. A regional hospital, located southeast of the intersection, would benefit from the serene setting and also be highly accessible. The conservation network provides recreational connections between the City Center and the reservoir areas, as well as a buffer for the segment of the Warm Springs Creek that flows through the site.

Finally, Site E lies within the proposed conservation corridor east of the Domenigoni Valley Reservoir, which is under construction. This area currently connects key areas of natural habitat while simultaneously allowing rural residential development. Orchards and horse farms are common in this area (Figure 47).

Trend development would continue to fragment the landscape, reducing wildlife habitat, fire management capacity, and the visual sense of an open landscape (Figure 48). Soil erosion and downstream flooding would accelerate as a result of the clearing of vegetation around houses and building of roads on steep slopes.

The design strategy is to cluster residential development as much as possible, maintaining larger areas of natural vegetation as habitat and for wildlife movement and enabling a program of fire management (Figure 49).

In the design, the same number of houses are clustered with natural vegetation maintained along property lines. As a result, considerably more area surrounding the houses has been left open for wildlife movement and fire management (Figure 50).