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| Cost Effective Landscape: Learning from Nature |
| Part 4: Monitor implementation |
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River diversion Inform site workers of key objectives - capitalise on opportunities. The Evan Water was diverted in 1995 ahead of the A74 upgrading to motorway. A design was produced with the prime objectives of maximising the ecological and landscape potential of the diversion. The degree of success of the project was dependent to a large extent on the attention paid to the characteristics of the underlying rock as it was unearthed. In this example the harder rock strata was utilised to create an unplanned constriction and sequence of rapids. This initiative eliminated the costs of excavation and subsequent re-creation of a man made constriction elsewhere and resulted in a more valuable solution. It is important that site staff understand the objectives and spirit of the design so that they can identify opportunities and use their initiative. Evan Water River diversion. 1995 Evan Water River diversion. 1995 Evan Water River diversion. 1997 Succession
Use natural characteristics - capitalise on findings. This superseded road has been reduced in width. One carriageway has been broken up and covered with a mixture of topsoil and pulverised wood waste from the site. It was not considered necessary to remove the road surface because the topsoil was to be converted into natural woodland as opposed to agricultural land. The contract required the area to be cultivated and seeded with commercially available grass seed but a variation was agreed to cultivate and seed only a 1.5 metre strip adjacent to the carriageway to establish grass. The objective being to reduce the process of succession to scrub and woodland and preserve a safe and functional working width of the road. The remainder of the verge could be allowed to regenerate naturally. The site monitoring and an understanding of natural regeneration resulted in cost savings and a better result. This opportunity was only possible because the adjacent vegetation is semi-natural and contains no noxious weeds and the soil placed on the carriageway was similar to that in the woodland. Due to the unpredictability of natural regeneration, the progress will need to be monitored. Logie Easter - Garrick Bridge. August 1997 Capitalise on findings Where vegetation has become established naturally on finished earthworks during the construction period, it may be preferable to allow this to remain rather than comply with the original requirements to sow seed into clean cultivated ground. In this situation on the A9 at Logie Easter, the landscape design objective is to integrate the roadside with the adjacent landscape character. The acidic ground conditions and vegetation assemblages that have become established are ideal to meet these design objectives. If the grass were to be sown as specified, it would require the spontaneous vegetation to be treated with herbicide, the surface soil cultivated and seeded with commercially available grass seed. The natural vegetation would then compete with the artificially seeded grasses and eventually become established on the site. Working with nature rather than against it, and allowing the spontaneous growth to remain will achieve better than planned results at lower than predicted costs. It illustrates, in a modest but worthwhile way, how monitoring construction and capitalising on the findings that economic and environmental benefits can be complementary. A9, Logie Easter - Garrick Bridge. August 1997 A9, Logie Easter - Garrick Bridge. August 1997 Erratic Explore alternatives - Capitalise on findings. Finding unexpected and unforeseen objects and situations are commonplace during construction. Consideration should be given to exploiting such situations to advantage. This stone is likely to be a glacial erratic which the contractor may wish to dump, break up and use for construction. Or... It could be placed safely nearby to become an interesting focal point. A9, Logie Easter - Garrick Bridge. Rock cascade Capitalise on findings - use natural characteristics The contract required this cascade and culvert to be constructed from concrete. The excavations unearthed fairly large slabs of stone. The contractor was experienced in handling and using natural stone for building and so proposed that the stone be used as an alternative to concrete. This was accepted. Resources were used wisely, the design has been improved, and the contractor gained added job satisfaction. The stone with it's natural colour, patterns, texture and irregular form contrasts markedly with the equivalent concrete structure. Natural stone assists in the integration of engineering features and may make them more attractive to some forms of wildlife. Wise use of resources generated on the site makes good economic sense for contractor, client and employer alike and can contribute to sustainable development. Tub grinder Wise use of resources. The Environmental Management Plan for the A74 upgrading to M6 prohibits the burning of tree stumps. The tub grinder was hired to convert the stumps into wood chips for re-use as a planting mulch on the site. This policy requires alternative solutions to be examined and environmental consequences assessed. It might be that some of the stumps could be retained and arranged on the surface close to their original location to form valuable wildlife habitats. They would attract a diverse variety of insects, invertebrates and small mammals whilst also providing fodder for birds. Another alternative would be to use some of them in the adjacent newly constructed river diversion to guide wildlife to underpasses and create otter holts and habitats for birds. It is also conceivable that some of them could be induced to grow. The landscape designer shall always seek ways to use waste materials positively A9, Logie Easter (March 1997) "What shall we do with the stumps?" |
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