In policy contexts valuations may be required not only for the most inclusive good considered but also the relevant sub-areas or components which are nested within the broader good. Valuation of differing levels of quantity/quality, referred to here as scope, provides many challenges to the researcher. Through considering the sensitivity of welfare measures to scope and the valuation sequence used, this thesis was undertaken to investigate the difficulties in and prospects for using CV to estimate the non-market value of nested goods. Using a mixed methodology survey design, the case study focuses on the use of the contingent valuation method to estimate non-market benefits from a saline flood alleviation scheme in Broadland, located in Eastern England. A scheme to protect the `whole' area from saline flooding was compared to five separate `part' schemes which would only protect nested sub-areas of Broadland. Insensitivity to scope was observed within both a split sample comparison of `whole' and `part' valuations and a same sample comparison where the `part' scheme was valued first. The prior valuation of the `whole' scheme did induce sensitivity to scope between `whole' and `part' schemes, but this effect can be interpreted in terms of either economic theory, consistency pressures or the use of a more natural valuation sequence. However, the prior valuation of the `whole' scheme also induced split sample sensitivity to good characteristics between the `part' schemes. Overall the explanation for the results given cannot be monopolised by either contingent valuation supporters or their critics. In the case of Broadland flood alleviation, the validity of the valuations presented remains unclear but some interesting findings suggest future directions for research.

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This thesis explores several important hydrological modelling topics surrounding the use of continuous rainfall-runoff simulation for flood frequency estimation. A continuous simulation methodology suitable for flood frequency estimation is developed. The methodology features a rainfall-runoff model (TOPMODEL, e.g. Beven, 1997), a new profile-based stochastic rainfall model (developed in this thesis), and an uncertainty estimation procedure (Generalised Likelihood Uncertainty Estimation, or GLUE e.g. Beven and Binley, 1992). By explicitly accounting for a catchment's soil moisture conditions, allowing the direct simulation of long return period flood events (via the coupling of TOPMODEL with the stochastic rainfall model), and quantifying the uncertainty associated with the simulated flood estimates, this methodology is an attractive alternative to the more traditional statistical and event-based techniques available for flood frequency estimation. It is tested successfully using data obtained from five, gauged, UK catchments. In addition to exploring the possible consistency between flood peak and continuous flow rainfall-runoff model parameterisations, the methodology is used to examine the potential impacts of climatic change upon flood frequency. Two further issues are also addressed. These are: the choice of stochastic rainfall model (for use within continuous simulation studies), and the modification of a pulse-based stochastic rainfall model for enhanced extreme rainfall simulation.

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The scale-bound view of landsurfaces, being an assemblage of certain landforms, occurring within limited scale ranges, has been challenged by the scale-free characteristics of fractal geometry. This thesis assesses the fractal model by examining the irregularity of landsurface form, for the self-affine behaviour present in fractional Brownian surfaces. Different methods for detecting self-affine behaviour in surfaces are considered and of these the variogram technique is shown to be the most effective. It produces the best results of two methods tested on simulated surfaces, with known fractal properties. The algorithm used has been adapted to consider log (altitude variance) over a sample of log (distances) for: complete surfaces; subareas within surfaces; separate directions within surfaces. Twenty seven digital elevation models of landsurfaces arc re-examined for self- affine behaviour. The variogram results for complete surfaces show that none of these are self-affine over the scale range considered. This is because of dominant slope lengths and regular valley, spacing within areas. For similar reasons subarea analysis produces the non-fractal behaviour of markedly different variograms for separate subareas. The linearity of landforms in many areas, is detected by the variograms for separate directions. This indicates that the roughness of landsurfaces is anisotropic, unlike that of fractal surfaces. Because of difficulties in extracting particular landforms from their landsurfaces, no clear links between fractal behaviour, and landform size distribution could be established. A comparative study shows the geomorphometric parameters of fractal surfaces to vary with fractal dimension, while the geomorphometry of landsurfaces varies with the landforms present. Fractal dimensions estimated from landsurfaces do not correlate with geomorphometric parameters. From the results of this study, real landsurfaces would not appear to be scale- free. Therefore, a scale-bound approach towards landsurfaces would seem to be more appropriate to geomorphology than the fractal alternative.

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