H22D-01
Optimal Management of Nitrate Pollution of Groundwater in Agricultural Watersheds Considering Environmental and Economic Constraints
Groundwater pollution due to nitrogen species from various land use activities and practices is a common concern in most agricultural watersheds. Minimization of nonpoint source nitrogen pollution can be achieved by appropriate changes to land use practices to the extent of not affecting local economies that depend heavily on agricultural activities. Most prior research work focused on predicting nitrogen loading and/or fate and transport of nitrate in groundwater due to various agricultural activities. In this work, however, we propose to present a broad integrated methodology for the optimal management of nitrate contamination of ground water combining environmental assessment and economic cost evaluation through multi-criteria decision analysis. The proposed methodology incorporates an integrated physical modeling framework accounting for on-ground nitrogen loading and losses, soil nitrogen dynamics, and fate and transport of nitrate in ground water to compute the sustainable on-ground nitrogen loading such that the maximum contaminant level is not violated. A number of protection alternatives to stipulate the predicted sustainable on-ground nitrogen loading are evaluated using the decision analysis that employs the importance order of criteria approach for ranking and selection of the protection alternatives. The methodology was successfully demonstrated for the Sumas-Blaine aquifer in Washington State. The results showed the importance of using this integrated approach that predicts the sustainable on-ground nitrogen loadings and provides an insight to the economic consequences generated in satisfying the environmental constraints. The results also show that the proposed decision analysis framework, within certain limitation, is effective when selecting alternatives with competing demands.
H22D-02
Plantation Forestry and Peak Flow Responses in Experimental Catchments and Large River Basins in Chile
Land use changes are inextricably linked to water resources and the consequences of such changes are a problem faced by water managers and governments across the world. This particular study considers the impact of changes in plantation forest cover on the hydrological response, with a specific focus on the issue of peak flow conditions and variation. The research still in progress is focused in small catchments and large river basins of Chile. The analysis of the data and the preparation of this document were carried out within the framework of the INCO- CT2004-510739 EPIC FORCE Project. EPIC FORCE aims to improve the integrated management of forest and water resources at the river basin scale through the development of policies based on sound science, focusing on extreme rainfall/snowmelt events. The focus areas are four Latin American countries (Costa Rica, Ecuador, Chile and Argentina.), which represent a range of humid forest and rainfall/snowmelt regimes with major flood and erosion problems and which suffer from a lack of integrated water and forest policies. Much of the controversy surrounding changes in peak flows following forest treatment arises from uncertainty over the response from different sizes of storms; whilst most studies agree that mean peak flow generally increases (even for only a short period) in the post harvesting period, there have been a number of different conclusions regarding influence of forest cover on peak flows from small storms compared with the flows from large events. In Chile, this research is been carried out in experimental catchments (less than 1 km2) and in large river basins (greater than 94 and up to 1,545 km2). Results from La Reina (34.4 ha), where peak flows from the pre-harvesting period (years 1997 to 1999, plantation of Pinus radiata established in 1977 covering the 79.5% of the area) were compared with those from the post- harvesting period (plantation clearcut between end of 1999 and first months of 2000 and replaced by an Eucalyptus nitens plantation) show that in average peak flows increased by 32% after forest removal. Analyzing pre and post-harvesting peak flows from different sizes of rainfall events (rainfall "small" events from 5 to 10 mm, "medium" events from 10 to 50 mm, and "large" events greater than 50 mm), the median of the peak flows increased by 67% for the small events and 32% for the large events. Besides, comparing the pre-harvesting condition with each of the years of the post-harvesting period (years 2000 to 2005), the analysis showed that in all cases post-harvesting peak flows were still significantly higher than before forest clearing. Decreases in annual runoff were noticed in the large river basins where forested area almost doubled between the beginnings of the 1970 up to present. These decreases in annual runoff are well explained by the increases in evapotranspiration capacity of the new planted forests, calculated using the Zhang model and through direct measurements done in experimental plots by the authors. However, the increases in planted area within these large river basins seem not to affect peak flows, as peak flows from the "pre plantation development period" were not statistically different from those of the "post plantation development" one. This research is allowing the generation of evidence based management proposals to support forest certification processes of Chilean companies.
H22D-03
A GENERIC FRAMEWORK FOR WATER AND FOREST MANAGEMENT IN CATCHMENTS RESTORATION IN LATIN AMERICA
The document presents a generic framework for the analysis and development of a programme for catchment management and restoration that takes into account both the protection from the impact of extreme events and the sustainable use of land and water resources. The framework was originally developed for the restoration of mountain catchments in Europe between the end of the 19th century and the beginning of the 20th century and still provides the intellectual basis for the integrated assessment of hydraulic and land use factors in these countries. It is based on a thorough analysis of the behavior of a catchment in normal and extreme conditions. Recently, the authors have tested this generic framework in a number of catchments in Latin America, which present very different physical and socio-economic conditions. Fieldwork in Costa Rica, Ecuador, Chile and Argentina with particular catchments covering a whole range of climatological, geo-morphological and land used settings has provided new insights on the applicability of this generic framework. The paper discusses the role of vegetation, and in particular of forests, in catchment management taking a long-term view of cost and benefits under normal and extreme conditions. It also provides conclusions for the development of land use policies to optimize the practical use of vegetation of management purposes.
H22D-04
Policy Recommendations for the Argentinean Water Resources National Plan Related to Extreme Events in Forested Mountain Basins.
In the framework of activities developed by COHIFE (Federal Water Resource Council), Argentina is preparing the
Water Resources National Plan. To achieve an integrating project and considering that Argentina is a federal
country, each province is working on the basis of its own Water Resources Provincial Plan.
The first step of the plan consists in the identification of problems, with the purpose of further defining solutions
based on structural and non structural actions. The general perception of the stakeholders involved in the plan
development is the necessity of the analysis of strategies for the integrated water resource management
Although a first document for water policy, named "Principios Rectores de Política Hídrica" is available, there
are not specific strategies for integrated management of water and land use oriented to extreme events. In other
way, there are a lack of policies oriented to Mountain basin with forest coverage, may be because of most of the
population and the economical structure of the country is located on plain regions.
This article proposes recommendations for policy to be integrated to the Water Resources National Plan, based
on studies developed in a pilot basin representative of the Andean-Patagonia eco-region, in the framework of the
EPIC FORCE proyect, financed by the European Union. Project methodology includes basin instrumentation,
reconstruction and analysis of extreme events and land-water management practices revision. Climate, flow and
sediment Data are available for simulation using the Shetran model on different land use scenarios, including
changes in the basin forest coverage.
On the basis of the first results of the project, policy guides oriented to fill mentioned policy lacks were defined.
http:www.ceg.ncl.ac.uk/epicforce/
H22D-05
Defining Scenarios: Linking Integrated Models, Regional Concerns, and Stakeholders
Scenarios are important tools for long-term planning, and there is great interest in using integrated models in
scenario studies. However, scenario definition and assessment are creative, as well as scientific, efforts. Using
facilitated creative processes, we have worked with stakeholders to define regionally significant scenarios that
encompass a broad range of hydroclimatic, socioeconomic, and institutional dimensions. The regional
scenarios subsequently inform the definition of local scenarios that work with context-specific integrated models
that, individually, can address only a subset of overall regional complexity. Based on concerns of stakeholders in
the semi-arid US Southwest, we prioritized three dimensions that are especially important, yet highly uncertain,
for long-term planning: hydroclimatic conditions (increased variability, persistent drought), development patterns
(urban consolidation, distributed rural development), and the nature of public institutions (stressed, proactive).
Linking across real-world decision contexts and integrated modeling efforts poses challenges of creatively
connecting the conceptual models held by both the research and stakeholder communities.
http:www.sahra.arizona.edu/scenarios
H22D-06
An Assessment of long term Climate Change Impacts in a Riparian System: The San Pedro Basin
While a broad range of literature exists regarding regional climate forecasting using global circulation models (GCM) and downscaling techniques to assess hydrologic impacts, these often focus on relatively short lead times, use daily time steps, and focus on particular events such as low flows, extreme events, etc. However, few publications seem to focus on the long term evolution of a basin's water balance due to climate change impacts on regional hydrologic processes. And yet, this may be the most beneficial application of hydro-climatology to support long term water resources management and planning. A study in the San Pedro Basin contributes to this domain by modeling hydrologic impacts of IPCC climate change scenarios by downscaling - spatially and temporally - data from an ensemble of global circulation models over the next century. Depending on how climate change affects seasonal precipitation regimes, the impacts on ground water recharge are susceptible to vary significantly. Long-term changes in the basin's water budget are assessed using existing hydrological models for the San Pedro Basin. As this work provides a basis for the inclusion of climatic scenarios into the Basin's decision and policy-making process, an effort is made to clearly present a broad range of results corresponding to different scenarios for water managers and policy makers.
H22D-07
Central American climate change consensus and implications for Rio Lempa streamflow
We combine 21st century projections from 32 global climate model (GCM) simulations produced for the
Intergovernmental Panel on Climate Change Fourth Assessment, 16 GCMs each using both the lower SRES B1
and the higher SRES A2 greenhouse gas emissions scenarios. We use an established statistical downscaling
procedure to produce sequences of precipitation and temperature over the Rio Lempa basin, the largest river
system in Central America and an important resource for water supply and hydropower generation. We use a
spatially distributed hydrologic model to integrate these climate projections into streamflow. Assuming each
projection is equally probable, we examine the level of consensus among model projections for each emissions
scenario for precipitation, temperature, and streamflow. For the end of the 21st century, the basin has a median
temperature increase of 3.4C under A2 and 1.9C under B1, both of which are highly significant and significantly
different. Annual rainfall declines by 10 percent under A2 and 5 percent under B1. Rainfall decreases are highly
significant, as are differences between A2 and B1 for April-June. With the projected drying occurring in the early
rainy season, the bimodal characteristic of the rainy season becomes less pronounced. GCMs projecting greater
warming tend to project drier conditions than those projecting less warming. The consensus of the projections is
for a seasonal shift in Rio Lempa flows, with annual flows dropping by 13 percent under lower emissions and 24
percent under higher emissions, with the peak flow decrease of 35-40 percent in June-August, months during
which reservoir refilling has historically occurred.
http:www.engr.scu.edu/~emaurer
H22D-08
Understanding the role of dynamical climate variations for Water Resources Decision-Making and Sustainability Considerations
Recent research linking dynamical climate variations to surface water supplies provides two important considerations for sustainable water resources management and rulemaking: (1) The changing envelope of climate variability over the last century is mirrored in water supplies as shifts in the metrics of hydrologic variability--trends in mean and variance of runoff, shifts in seasonality, and frequency of floods and droughts--of relevance to planning, management and design. (2) An improved understanding of the low-frequency (annual to decadal and longer time scale) climate variations promise a foreknowledge of regional hydrologic variability, thus opening a way to develop predictive tools that use climate precursors as a guide to proactively adapt water resources management and operating plans on within-year and longer time scales. Some examples from the current research in this emerging research area linking climate to managed and natural hydrologic systems are presented. Implications of this research for Sustainable Water Use Rulemaking and Management for eastern and western North America are discussed.