## 3 Methodology  
This section may be divided by subheadings. It should provide a concise and precise description of the experimental results, their interpretation, as well as the experimental conclusions that can be drawn. A robust review technique was created to provide a complete and traceable evaluation. For this purpose, review methods serve as a foundation for the review process, reducing researcher bias. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram from Prisma-statement.org [81] was used in this investigation. The information flow across the several phases of a systematic review is depicted in the PRISMA flow diagram. Identifying all possibly relevant data, choosing eligible research, determining bias risk, data extraction, qualitative synthesis of the studies included, and likely meta-analysis [82] are all express and inducible procedures in the systematic review (Figure 1). [PERSON] et al. [83] exhibited the PRISMA flow diagram in a systematic review, and [PERSON] et al. [84] did the same in a study. The review process was depicted using a diagrammatic presentation. Figure 1: PRISMA framework method steps. Using the PRISMA conceptual framework as a foundation (Figure 1), we created a search string to search the abstract, title, and keywords of literature in the online database \"Scopus\". The literature sample was compiled from peer-reviewed journal articles published in English between January 2000 and May 2022. On 15 May 2022, the search process was completed. The procedure went through four steps (Figure 2) before obtaining the 117 most important studies on groundwater level change modeling using machine learning and mathematical model techniques. The search string was designed to suit specific exact keywords, such as \"groundwater\", \"mathematical models\", \"groundwater flow\", \"groundwater resources\", \"climate change\", \"computer simulation\", \"numerical model\", \"statistical model\", \"machine learning\", and \"groundwater level changes\", through a well-thought-out search strategy. Many articles were found using the search query, but many were eliminated during the title and abstract screening phase. The search string appears in the text field (Table 1) below. \begin{table}
\begin{tabular}{l} \hline \hline
**The Search String** \\ \hline TITLE-ABS-KEY((MACHINE LEARNING AND GROUNDWATER LEVEL CHANGES) OR (MATHEMATICAL MODELS AND GROUNDWATER LEVEL CHANGES) AND (LIMIT-TO (PUBYEAR, 2022) OR LIMIT-TO (PUBYEAR, 2021) OR LIMIT-TO (PUBYEAR, 2020) OR LIMIT-TO (PUBYEAR, 2019) OR LIMIT-TO (PUBYEAR, 2017) OR LIMIT-TO (PUBYEAR, 2016) OR LIMIT-TO (PUBYEAR, 2015) OR LIMIT-TO (PUBYEAR, 2014) OR LIMIT-TO (PUBYEAR, 2013) OR LIMIT-TO (PUBYEAR, 2012) OR LIMIT-TO (PUBYEAR, 2011) OR LIMIT-TO (PUBYEAR, 2010) OR LIMIT-TO (PUBYEAR, 2009) OR LIMIT-TO (PUBYEAR, 2008) OR LIMIT-TO (PUBYEAR, 2007) OR LIMIT-TO (PUBYEAR, 2006) OR LIMIT-TO (PUBYEAR, 2005) OR LIMIT-TO (PUBYEAR, 2005) OR LIMIT-TO (PUBYEAR, 2004) OR LIMIT-TO (PUBYEAR, 2001) OR LIMIT-TO (PUBYEAR, 2005) OR LIMIT-TO (PUBYEAR, 2003) OR LIMIT-TO (PUBYEAR, 2000) OR LIMIT-TO (PUBYEAR, 2000) AND (LIMIT-TO (DCCTYPE, “ar”)) AND (LIMIT-TO (EXACTKEYWORD, “Groundwater”) OR LIMIT-TO (EXACTKEYWORD, “Mathematical Models”) OR LIMIT-TO (EXACTKEYWORD, “Groundwater Flow”) OR LIMIT-TO (EXACTKEYWORD, “Groundwater Resources”) OR LIMIT-TO (EXACTKEYWORD, “Climate Change”) OR LIMIT-TO (EXACTKEYWORD, “Computer Simulation”) OR LIMIT-TO (EXACTKEYWORD, “Numerical Model”) OR LIMIT-TO (EXACTKEYWORD, “Ground Water”)) AND (LIMIT-TO (LANGUAGE, “English”) AND (LIMIT-TO (