Cost-Benefit Analysis in Planning Processes: An Interactive Instrument in an Integrated Approach

Increasing pressure on space demands careful assessment between competing functions in a planning process. Especially, in metropolitan landscapes, space is in short supply and hence expensive. Housing, industrial sites and office parks, and infrastructure are strong drivers of landscape change, often dominating nature and landscape which represent values with a more collective good character. Nevertheless, in The Netherlands, nature is becoming an important force in spatial planning. This assessment between competing functions, requires interactive planning and appropriate instruments. In the usual planning process, the costs and benefits of the development plans to society are only computed in the final stage of the process. We argue in this paper for integration of a social cost-benefit analysis (SCBA) in interactive regional planning processes. Firstly, it avoids time and money being spent on elaborating a plan, which is not beneficial to society. Secondly, it helps to prevent unwarranted enthusiasm for inauspicious plans among participants. From earlier studies, we learned that in the application of SCBA the discussion between researchers, clients and other participants should focus on two or three clearly distinctive models. Too much detail should be avoided. On the other hand, key indicators used in calculating effects have to be available and well documented. The summation of the costs and benefits provides a first impression of the financial and social feasibility of the plan. In a first planning session, therefore, a common understanding of the mechanisms underlying the assessment of the plan will be built up. This improves the support for SCBA of the final project. It also provides the stakeholders and shareholders with information about the feasibility of the plan at an early stage. Another advantage is that SCBA focuses on the benefits to society as a whole. Recently, we have spent much effort in the development of an interactive tool that is both relevant and user friendly. Relevant means that it takes into account the essential values of different types of land use and their interaction. At the moment we focus on spatial interaction and incorporating ecological network values. A prototype of the interactive integrated model is available for demonstration.

Cost-effectiveness analysis of water policy measures for nutrients: a regional model

Abstract: This paper presents a regional economic optimization model, the RegiOptimizer, which is an integrated regional water and economy model that links economic costs to water quality improvements. RegiOptimizer has two strengths compared to similar models. Firstly, the model imposes policy targets on substance concentration levels for water quality (not emissions levels). Secondly, the current model includes the levels of nitrogen and phosphate concentrations of surface water. As a result, the model takes into account the interaction of measures with respect to the reduction of nitrogen and phosphates concentration levels. The results of the RegiOptimizer for the case study region, the Beerze and Reusel river basin in the South of the Netherlands show large synergies between the reduction of nitrogen and phosphates. Furthermore, the water quality will improve locally although the WFD targets will not be reached yet. If the neighbouring countries (Belgium) achieve the WFD objective, Beerze and Reusel river basin will benefit significantly in terms of lower costs for implementing measures

A CANDELS - 3D-HST Synergy: Resolved Star Formation Patterns at 0.7 < z < 1.5

We analyze the resolved stellar populations of 473 massive star-forming galaxies at 0.7 < z < 1.5, with multi-wavelength broad-band imaging from CANDELS and Halpha surface brightness profiles at the same kiloparsec resolution from 3D-HST. Together, this unique data set sheds light on how the assembled stellar mass is distributed within galaxies, and where new stars are being formed. We find the Halpha morphologies to resemble more closely those observed in the ACS I band than in the WFC3 H band, especially for the larger systems. We next derive a novel prescription for Halpha dust corrections, which accounts for extra extinction towards HII regions. The prescription leads to consistent SFR estimates and reproduces the observed relation between the Halpha/UV luminosity ratio and visual extinction, both on a pixel-by-pixel and on a galaxy-integrated level. We find the surface density of star formation to correlate with the surface density of assembled stellar mass for spatially resolved regions within galaxies, akin to the so-called 'main sequence of star formation' established on a galaxy-integrated level. Deviations from this relation towards lower equivalent widths are found in the inner regions of galaxies. Clumps and spiral features, on the other hand, are associated with enhanced Halpha equivalent widths, bluer colors, and higher specific star formation rates compared to the underlying disk. Their Halpha/UV luminosity ratio is lower than that of the underlying disk, suggesting the ACS clump selection preferentially picks up those regions of elevated star formation activity that are the least obscured by dust. Our analysis emphasizes that monochromatic studies of galaxy structure can be severely limited by mass-to-light ratio variations due to dust and spatially inhomogeneous star formation histories.Comment: Accepted by The Astrophysical Journal, 18 pages, 1 table, 10 figure

The lack of star formation gradients in galaxy groups up to z~1.6

In the local Universe, galaxy properties show a strong dependence on environment. In cluster cores, early type galaxies dominate, whereas star-forming galaxies are more and more common in the outskirts. At higher redshifts and in somewhat less dense environments (e.g. galaxy groups), the situation is less clear. One open issue is that of whether and how the star formation rate (SFR) of galaxies in groups depends on the distance from the centre of mass. To shed light on this topic, we have built a sample of X-ray selected galaxy groups at 0<z<1.6 in various blank fields (ECDFS, COSMOS, GOODS). We use a sample of spectroscopically confirmed group members with stellar mass M >10^10.3 M_sun in order to have a high spectroscopic completeness. As we use only spectroscopic redshifts, our results are not affected by uncertainties due to projection effects. We use several SFR indicators to link the star formation (SF) activity to the galaxy environment. Taking advantage of the extremely deep mid-infrared Spitzer MIPS and far-infrared Herschel PACS observations, we have an accurate, broad-band measure of the SFR for the bulk of the star-forming galaxies. We use multi-wavelength SED fitting techniques to estimate the stellar masses of all objects and the SFR of the MIPS and PACS undetected galaxies. We analyse the dependence of the SF activity, stellar mass and specific SFR on the group-centric distance, up to z~1.6, for the first time. We do not find any correlation between the mean SFR and group-centric distance at any redshift. We do not observe any strong mass segregation either, in agreement with predictions from simulations. Our results suggest that either groups have a much smaller spread in accretion times with respect to the clusters and that the relaxation time is longer than the group crossing time.Comment: Accepted for publication in MNRA

Smooth(er) Stellar Mass Maps in CANDELS: Constraints on the Longevity of Clumps in High-redshift Star-forming Galaxies

We perform a detailed analysis of the resolved colors and stellar populations of a complete sample of 323 star-forming galaxies at 0.5 < z < 1.5, and 326 star-forming galaxies at 1.5 < z < 2.5 in the ERS and CANDELS-Deep region of GOODS-South. Galaxies were selected to be more massive than 10^10 Msun and have specific star formation rates above 1/t_H. We model the 7-band optical ACS + near-IR WFC3 spectral energy distributions of individual bins of pixels, accounting simultaneously for the galaxy-integrated photometric constraints available over a longer wavelength range. We analyze variations in rest-frame color, stellar surface mass density, age, and extinction as a function of galactocentric radius and local surface brightness/density, and measure structural parameters on luminosity and stellar mass maps. We find evidence for redder colors, older stellar ages, and increased dust extinction in the nuclei of galaxies. Big star-forming clumps seen in star formation tracers are less prominent or even invisible on the inferred stellar mass distributions. Off-center clumps contribute up to ~20% to the integrated SFR, but only 7% or less to the integrated mass of all massive star-forming galaxies at z ~ 1 and z ~ 2, with the fractional contributions being a decreasing function of wavelength used to select the clumps. The stellar mass profiles tend to have smaller sizes and M20 coefficients, and higher concentration and Gini coefficients than the light distribution. Our results are consistent with an inside-out disk growth scenario with brief (100 - 200 Myr) episodic local enhancements in star formation superposed on the underlying disk. Alternatively, the young ages of off-center clumps may signal inward clump migration, provided this happens efficiently on the order of an orbital timescale.Comment: Accepted by The Astrophysical Journal, 27 pages, 1 table, 16 figure

The SINS/zC-SINF survey of z~2 galaxy kinematics: Outflow properties

Based on SINFONI Ha, [NII] and [SII] AO data of 30 z \sim 2 star-forming galaxies (SFGs) from the SINS and zcSINF surveys, we find a strong correlation of the Ha broad flux fraction with the star formation surface density of the galaxy, with an apparent threshold for strong outflows occurring at 1 Msun yr^-1 kpc^-2. Above this threshold, we find that SFGs with logm_\ast>10 have similar or perhaps greater wind mass loading factors (eta = Mdotout/SFR) and faster outflow velocities than lower mass SFGs. This trend suggests that the majority of outflowing gas at z \sim 2 may derive from high-mass SFGs, and that the z \sim 2 mass-metallicity relation is driven more by dilution of enriched gas in the galaxy gas reservoir than by the efficiency of outflows. The mass loading factor is also correlated with the SFR and inclination, such that more star-forming and face-on galaxies launch more powerful outflows. For galaxies that have evidence for strong outflows, we find that the broad emission is spatially extended to at least the half-light radius (\sim a few kpc). We propose that the observed threshold for strong outflows and the observed mass loading of these winds can be explained by a simple model wherein break-out of winds is governed by pressure balance in the disk. Using the ratio of the [SII] doublet in a broad and narrow component, we find that outflowing gas has a density of \sim10-100 cm^-3, significantly less than that of the star forming gas (600 cm^-3).Comment: 7 pages, 3 figures, accepted by Ap

Galaxy kinematics and mass estimates at z ∼ 1 from ionised gas and stars

We compare ionised gas and stellar kinematics of 16 star-forming galaxies (log (M⋆/M⊙) = 9.7 − 11.2, SFR =6 − 86M⊙/yr) at z ∼ 1 using near-infrared integral field spectroscopy (IFS) of Hα emission from the KMOS3D survey and optical slit spectroscopy of stellar absorption and gas emission from the LEGA-C survey. Hα is dynamically colder than stars, with higher disc rotation velocities (by ∼45 per cent) and lower disc velocity dispersions (by a factor ∼2). This is similar to trends observed in the local Universe. We find higher rotational support for Hα relative to [OII], potentially explaining systematic offsets in kinematic scaling relations found in the literature. Regarding dynamical mass measurements, for six galaxies with cumulative mass profiles from Jeans Anisotropic Multi-Gaussian Expansion (JAM) models the Hα dynamical mass models agree remarkably well out to ∼10 kpc for all but one galaxy (average ΔΜdyn(Re, F814W) &lt; 0.1 dex). Simpler dynamical mass estimates based on integrated stellar velocity dispersion are less accurate (standard deviation 0.24 dex). Differences in dynamical mass estimates are larger, for example, for galaxies with stronger misalignments of the Hα kinematic major axis and the photometric position angle, highlighting the added value of IFS observations for dynamics studies. The good agreement between the JAM models and the dynamical models based on Hα kinematics at z ∼ 1 corroborates the validity of dynamical mass measurements from Hα IFS observations, which can be more easily obtained for higher redshift galaxies