East Africa (EA) has one of the world's fastest growing populations, with maxima around water-bodies and rapid urbanisation. Climate change is adding to existing problems increasing vulnerability of the poorest. HyCRISTAL is driven by EA priorities. EA communities rely on rainfall for food via agriculture. EA's inland lakes are rain-fed and provide water, power and fisheries. For EA's growing cities, climate impacts on water resources will affect water supply & treatment. HyCRISTAL will therefore operate in both urban & rural contexts.

Change in water availability will be critical for climate-change impacts in EA, but projections are highly uncertain for rain, lakes, rivers and groundwater, and for extremes. EA "Long-Rains" are observed to be decreasing; while models tend to predict an increase (the "EA Climate paradox") although predictions are not consistent. This uncertainty provides a fundamental limit on the utility of climate information to inform policy. HyCRISTAL will therefore make best use of current projections to quantify uncertainty in user-relevant quantities and provide ground-breaking research to understand and reduce the uncertainty that currently limits decision making.

HyCRISTAL will work with users to deliver world-leading climate research quantifying uncertainty from natural variability, uncertainty from climate forcings including those previously unassessed, and uncertainty in response to these forcings; including uncertainties from key processes such as convection and land-atmopshere coupling that are misrepresented in global models. Research will deliver new understanding of the mechanisms that drive the uncertainty in projections. HyCRISTAL will use this information to understand trends, when climate-change signals will emerge and provide a process-based expert judgement on projections. Working with policy makers, inter-disciplinary research (hydrology, economics, engineering, social science, ecology and decision-making) will quantify risks for rural & urban livelihoods, quantify climate impacts and provide the necessary tools to use climate information for decision making.

HyCRISTAL will work with partners to co-produce research for decision-making on a 5-40 year timescale, demonstrated in 2 main pilots for urban water and policies to enable adaptive climate-smart rural livelihoods. These cover two of three "areas of need" from the African Ministerial Council on Environment's Comprehensive Framework of African Climate Change Programmes. HyCRISTAL has already engaged 12 partners from across EA. HyCRISTAL's Advisory Board will provide a mechanism for further growing stakeholder engagement.

HyCRISTAL will work with the FCFA global & regional projects and CCKE, sharing methods, tools, user needs, expertise & communication. Uniquely, HyCRISTAL will capitalise on the new LVB-HyNEWS, an African-led consortium, governed by the East African Community, the Lake Victoria Basin Commission and National Meteorological and Hydrological agencies, with the African Ministerial Conference on Meteorology as an observer.

HyCRISTAL will build EA capacity directly via collaboration (11 of 25 HyCRISTAL Co-Is are African, with 9 full-time in Africa), including data collection and via targeted workshops and teaching. HyCRISTAL will deliver evidence of impact, with new and deep climate science insights that will far outlast its duration. It will support decisions for climate-resilient infrastructure and livelihoods through application of new understanding in its pilots, with common methodological and infrastructure lessons to promote policy and enable transformational change for impact-at-scale. Using a combination of user-led and science-based management tools, HyCRISTAL will ensure the latest physical science, engineering and social-science yield maximum impacts. HyCRISTAL will deliver outstanding outputs across FCFA's aims; synergies with LVB-HyNEWS will add to these and ensure longevity beyond HyCRISTAL.

Potential Impact:
HyCRISTAL will have a positive impact on 7 groups of beneficiaries through the process and research outcomes.
1) COMMUNITIES IN THE LAKE VICTORIA BASIN
Communities will have the opportunity to access, input to, and benefit via their livelihoods from the research. Development options and pathways for climate-smart fisheries/agriculture, sustainable water use, access & distribution, will enhance productive and WASH outcomes in the region with such measurable livelihood improvements as greater levels of savings or tradeable assets. At least 400 households will participate in the adaptation trials. Wider engagement will occur via community exchanges, district workshops and regional learning platforms.
2) WATER PLANNERS/MANAGERS IN GOVERNMENT & POLICY
Close links with resource planners and government policymakers (East African Community, Lake Victoria Basin Commission, Uganda National Water and Sewerage Co, Local Authorities) will facilitate the 2-way flow of information, tools & guidance needed to support livelihoods & water management. Training will be tailored to user needs and through inclusive participation, empower women & youth to co-design and better apply planning tools. These stakeholders will act as researcher-advocates and contribute to policy uptake via "fit-for-purpose" evidence of the pilot outcomes. Value-added impact of such interventions on the local economy & livelihoods will result from investments to Treasury & donors. Local/sub-national governments in the region now have devolved responsibilities for climate services and will also benefit from improved evidence of benefits.
3) INTERNATIONAL & BILATERAL DEVELOPMENT PARTNERS
These will benefit from robust quantitative & qualitative evidence to inform programmes of support to national innovation support systems (including advisory services, SME promotion, regulatory frameworks). USAID & EU, World Bank, UNEP, UNDP, WFP, WHO and others are active in this region and will be invited to participate in the high-level Learning Platforms.
4) NGOs
Close collaboration with international (Practical Action) & local NGOs (Rural Environment & Development Organisation, OSIENALA, Association for Strengthening Agricultural Research in Eastern & Southern Africa) will inform their livelihood and WASH programs development and provide evidence of their own interventions and modes of working with pilot communities.
5) CIVIL SOCIETY ORGANIZATIONS (CSOs) & MEDIA
CSOs, national/sub-national farmer/fisher & urban organizations will benefit from evidence supporting lobbying for improved water services and climate-smart fisheries/agriculture management. Some CSOs already provide innovation support services (Uganda National Farmers Federation) and will be able to use the project findings to enhance such service provision. Engagement with CSOs & the media (local FM stations) will raise awareness of the research process and outcomes (planning information & decision tools). Wider coverage of the research & analytical methods will help to showcase benefits & attract future investment, stimulating collaborations beyond HyCRISTAL
6) RESEARCH INSTITUTES & MET SERVICES
HyCRISTAL will work with weather forecasters, hydrologists, hydrogeologists & users of medium-long-range forecasts, through project partnerships. These partners benefit via access to improved climate risk information and by strengthening utility of their climate services at regional to community levels.
7) PRIVATE SECTOR
African companies (Kisumu Water and Sewerage Company) will benefit from exposure to the knowledge products helping to inform their future business plans. Communities across the region will indirectly benefit from improved innovation support policies and interventions that are evidence based and tuned to the ways in which they seek support in their innovation & livelihood decision-making resulting in increased household capacity to invest in new livelihood options as current ones become unsusustainable