4.3.1. Design Goals

Historically, many deliberate artificial aquatic systems have been designed and maintained to provide one or a few services, such as water conveyance and storage [27,114]. The exclusion of many such artificial waterbodies from protection within the U.S. apparently reflects that policymakers and legal frameworks value these systems almost exclusively for their intended, fully human-oriented purposes [23]. Planning for only one or a few ecosystem services, such as water storage and conveyance for flood control, can limit the ability of a deliberate artificial aquatic ecosystem to provide other services, especially when designers overbuild that system for its given purposes [27]. In many cases, the design goal itself can inherently produce a major ecological cost, as in wetland drainage by agricultural ditches [115,116], or can result in unintended disservices arising from synergies and trade-offs in ecosystem services [117,118]. Nonetheless, many designed artificial aquatic systems also provide a range of additional ecosystem services beyond the purpose of their design [15,89].

The designs of aquatic ecosystems, including both newly constructed waterbodies and restoration of degraded systems, increasingly seek to provide a portfolio of ecosystem services and functions through redesign of physical structure as well as changes in managemen<sup>t</sup> [119,120]. Urban dwellers appreciate open expanses of water in spaces where they go for recreation [121], and even modified or constructed waterbodies can mitigate pollutants and floods, cool the air, and provide spaces for recreational, spiritual, and community-building activities [70]. For example, the Los Angeles River, converted to a concrete flood chute and movie set for car chases in the mid-20th century, has recently become the focus of an ambitious revitalization project to improve water quality and sustain wildlife while also providing a greenway and other recreational opportunities [120]. Similar redesigns of channelized rivers have already demonstrated the benefits of design for a range of ecosystem services [122]. The Landscape Architecture Foundation has endorsed projects throughout the U.S. and around the world with similar methods and goals, specifically including stormwater management, water conservation, water quality, flood protection, and groundwater recharge alongside other environmental, social, and economic goals [22]. Deliberate artificial aquatic ecosystems like these tend to remain primarily human oriented, and not ecologically oriented, in their goals, however. Even restoration designs often explicitly and unapologetically include human-specific concerns, such as ease of maintenance, accessibility, recreational appeal, aesthetics, regulatory standards, finances, and property lines, alongside more ecologically oriented values [123–125].
