In expanding informal neighborhoods of cities in sub-Saharan Africa, sustainable management of storm and wastewater drainage is fundamental to improving living conditions. Planners debate the optimal combination between "green" or natural infrastructure, traditional "grey" infrastructure, and "blue" infrastructure, which mimics natural solutions using artificial materials. Many advocate for small-scale, niche experiments with these approaches in informal settings, in order to learn how to navigate the intrinsic constraints of space, contested land tenure, participation, and local maintenance. This paper reports the benefits and limitations of implementing and managing local green, blue and grey infrastructure solutions in an urban informal setting. We studied ten completed public space projects that featured urban drainage infrastructure in the informal neighborhood of Kibera, Nairobi. The analysis drew from ten surveys with project designers and seven semi-structured interviews with site managers. The studied spaces featured different combinations of green, grey, and blue drainage infrastructure that have evolved over years of operation, maintenance, and change in the settlement. All projects featured participation in design, mixed design methods, hybrid infrastructure, and community governance models with potential to interact successfully with municipal actors. Results show that involvement in the co-development of small-scale green infrastructure changed people's valuation, perception, and stewardship of nature-based systems and ecosystem services. These results have implications for the larger scale adoption, integration, and management of urban drainage infrastructure. They also suggest that hybrid systems of infrastructure and governance constitute a resilient approach to incremental and inclusive upgrading.

在扩大撒哈拉以南非洲城市的非正式社区时，暴风雨和废水排放的可持续管理对于改善生活条件至关重要。计划者争论“绿色”或自然基础设施，传统“灰色”基础设施和“蓝色”基础设施之间的最佳组合，这些组合模仿使用人工材料的自然解决方案。许多人主张在非正式环境中使用这些方法进行小规模的利基实验，以学习如何应对空间，有争议的土地使用权，参与和本地维护的内在约束。本文报告了在城市非正式环境中实施和管理本地绿色，蓝色和灰色基础设施解决方案的好处和局限性。我们在内罗毕基贝拉非正式社区研究了十个以城市排水基础设施为特色的已完成公共空间项目。该分析来自与项目设计师进行的十次调查以及与现场经理的七次半结构化访谈。所研究的空间具有绿色，灰色和蓝色排水基础设施的不同组合，这些基础设施经过多年的运营，维护和居民点变化而发展。所有项目都具有参与设计，混合设计方法，混合基础设施和社区治理模型的潜力，这些模型有可能与市政参与者成功互动。结果表明，参与小规模绿色基础设施的共同开发改变了人们对基于自然的系统和生态系统服务的评估，认识和管理。这些结果对城市排水基础设施的大规模采用，集成和管理具有重要意义。他们还建议，基础架构和治理的混合系统构成了增量和包容性升级的弹性方法。